- Jan 26, 2011
- 40
Actually, my first experiment will be done in a 5 gallon bucket. Wanna understand this a little bit better before I commit the entire pool to it. 
What's up with muriatic acid?
- Thread starter draythomp
- Start date
- Jan 26, 2011
- 40
Got two pounds of oxalic acid. First test with a quart of pool water is interesting. I don't have my test kit yet, but when you have the stuff, you can't help playing around. So, I put 10g of Oxalic in the quart of pool water and stirred it up. It precipitates something almost immediately. It is an extremely fine suspension that clouds the water a lot. It looks like that CYA test that Leslie's does. I measured TDS (total dissolved solids) at 3000 before the addition and 7000 after the precipitate formed. So, something radical happened with only 10 grams.
Right now I'm filtering it through a coffee filter to see what remains and to see how hard it will be to filter out of the pool (If I have the courage to go that far).
Darn, I wish that test kit would come in.
Right now I'm filtering it through a coffee filter to see what remains and to see how hard it will be to filter out of the pool (If I have the courage to go that far).
Darn, I wish that test kit would come in.
- Jan 26, 2011
- 40
OK, before I go further with this could one of the experts chime in??
I got my test kit (TF-100) today and it looks like my CH level is way, way, way the heck up there; I gave up on the CH test on my pool water. I don't want to just waste the reagents so I tested water taken directly from my sink reverse osmosis device. Twenty drops of R10, five drops of R11 and it was blue. I didn't bother with R12 because this would indicate not enough Ca to bother with. Then I went to the water faucet and got some. The water faucet is after a water softener using potassium chloride instead of salt. Twenty drops of R10, five of R11 and the water was pink; two drops of R12 turned it blue = CH of 20.
The reason I gave up on the pool water was because at 60 drops the solution had only turned clear, not blue. I went on up to 70 drops and it was still clear. The reason I did the test on the sink and RO was to get a little experience with the test.
Question: Based on the x10 factor my pool water is at least over CH=600 and I don't know the range of the test so I'm a little worried about just adding R12 hoping it will eventually turn blue. Does anyone know the range of this test?
If I run out of R12, what is that reagent? Can I get it locally so I don't have to wait for it to arrive?
I really want to get to the experiment part of this, but it will mean lots of tests of small amounts of pool water that I have tried to precipitate the Ca out of and that will chew away at the reagents.
Suggestions, comments, curses??
Oh, I got the little stirring device. That thing is so cool!! It reminds me of the chemistry classes in college on a smaller scale. Fun!
And another Oh, I corrected my CYA level that I mentioned above and what a HUGE difference that made. I'm running at 50 and I have turned my chlorine generator down to 10% and it still makes too much chlorine. I can lower it further or shorten the pool run time, so I'm not concerned. However, those folks, like me, that don't understand the importance of this stuff should try letting the level deteriorate over time (again, like I did) and see how bad it can be. My generator was working it's little heart out and just barely keeping up as well as plating itself with calcium sulphate because of the high usage. I should pay much more attention to what people on here say......sigh.
I got my test kit (TF-100) today and it looks like my CH level is way, way, way the heck up there; I gave up on the CH test on my pool water. I don't want to just waste the reagents so I tested water taken directly from my sink reverse osmosis device. Twenty drops of R10, five drops of R11 and it was blue. I didn't bother with R12 because this would indicate not enough Ca to bother with. Then I went to the water faucet and got some. The water faucet is after a water softener using potassium chloride instead of salt. Twenty drops of R10, five of R11 and the water was pink; two drops of R12 turned it blue = CH of 20.
The reason I gave up on the pool water was because at 60 drops the solution had only turned clear, not blue. I went on up to 70 drops and it was still clear. The reason I did the test on the sink and RO was to get a little experience with the test.
Question: Based on the x10 factor my pool water is at least over CH=600 and I don't know the range of the test so I'm a little worried about just adding R12 hoping it will eventually turn blue. Does anyone know the range of this test?
If I run out of R12, what is that reagent? Can I get it locally so I don't have to wait for it to arrive?
I really want to get to the experiment part of this, but it will mean lots of tests of small amounts of pool water that I have tried to precipitate the Ca out of and that will chew away at the reagents.
Suggestions, comments, curses??
Oh, I got the little stirring device. That thing is so cool!! It reminds me of the chemistry classes in college on a smaller scale. Fun!
And another Oh, I corrected my CYA level that I mentioned above and what a HUGE difference that made. I'm running at 50 and I have turned my chlorine generator down to 10% and it still makes too much chlorine. I can lower it further or shorten the pool run time, so I'm not concerned. However, those folks, like me, that don't understand the importance of this stuff should try letting the level deteriorate over time (again, like I did) and see how bad it can be. My generator was working it's little heart out and just barely keeping up as well as plating itself with calcium sulphate because of the high usage. I should pay much more attention to what people on here say......sigh.
Yes, the normal recommended CYA level for SWG pools is 60-80 ppm with 80 ppm preferred precisely for the reasons you state. With pools exposed to sunlight, it can make a very large difference in the SWG on-time and its related side effects including the rate of pH rise, amount of scaling, etc.
As for the CH test on your pool water, use a 10 ml sample size so that each drop of titrant will be 25 ppm instead of 10 ppm. Also, add 5 drops of the R-0012 hardness reagent titrant to the sample first and then add the 20 drops of R-0010 calcium buffer and the 5 drops of R-0011L indicator dye. That can help make the endpoint more distinct (you count the 5 drops of titrant in your total). If that still doesn't help, then you can dilute your pool water sample with RO (or distilled) water and retest.
As for the CH test on your pool water, use a 10 ml sample size so that each drop of titrant will be 25 ppm instead of 10 ppm. Also, add 5 drops of the R-0012 hardness reagent titrant to the sample first and then add the 20 drops of R-0010 calcium buffer and the 5 drops of R-0011L indicator dye. That can help make the endpoint more distinct (you count the 5 drops of titrant in your total). If that still doesn't help, then you can dilute your pool water sample with RO (or distilled) water and retest.
Sorry in advance for the long post.
Two comments/topics both in regards to reducing ch in my pebble-tech, swg pool that has impermeable scale on natural stone at waterline.
My CH is 650-750
1. Regarding putting a filter downstream of the SWG to catch the chunks it throws off when reversing...
I've thought about that, but unless you can segregate them from the flow, wouldn't the water circulating around them redissolve them?
I've thought about hanging a mesh bag (one of those stainless dryer lint trap bags) on mine.
Because of my concern that they redissolve I haven't bothered, I just pick them out by hand from the spa or baja when I see big ones.
Say my 20K gallon pool weighs 160K pounds.
If I want to go down 200ppm CH, that's 30 POUNDS of CH I have to remove?
That's gonn'a take an awful lot of little chunks.
2 - Using oxalic acid to precipitate ch.
Regarding not being able to control the scaling, won't any undersired scaling that ends up pool equipment/surfaces eventually redisolve after things go back to normal?
I couldn't help myself from stopping at ACE and picking up two 12oz tubs of "Savogran Wood Bleach" at $9 something each. (90+% pure oxalic according to their msds).
1. Put some distilled water in a glass. Can dissolve quite a bit of oxalic powder in the distilled water (in terms of pinches) before it won't dissolve any more.
Water stays Crystal clear.
2. Add 10% that water to 90% pool water - immediately forms milky precipitate (that did not immediately settle) as desribed in Solarboys recent experiences.
3. Similarly, Add a tiny pinch to 100% pool water, same precipitate.
4. Run these samples through coffee filter (how's that compare to my Pentair cartridges?) and very little (1/4 maybe) was caught.
5. Tested PH (way) below my testers minimum 6.8. (dark yellow, like my cl tester when cl is 5+)
6. Used baking soda (a pinch) to get one glass up to 7.4. No noticeable change in precipitate
(I expected more because I thought solubility of ch was lower at higher ph?)
7. Added a teaspoon or so to half a homedepot (5gal) bucket of pool water.
Got mily precipitate.
Added a couple of drops of the blue liquid clarifier to a glass of water, stirred and added to 2.5gal in bucket.
8. Finally, I had my first experimental glass where I had added the distilled/oxalic mixture to pool water and was all milky.
I poured it out, and as Chem Geek predicted, the glass was awful.
All dingy with a film of "water spots". It wiped off easily with my finger, but I left it.
I filled the glass with pool water and we'll see if it redisovles.
Hopefully when I get up tomorrow:
1. Glass with 10% distilled/oxalic to 90% pool - precipitate settled as fine dust..
2. Glass with oxalic, pool, baking soda - greater amount of precipitate settled as fine dust.
3. HD bucket with pool water, oxalic and dash of blue clarifier, clumped/coagulated and settled.
Since I can't vacuum to waste, I'll stir some of the bucket up and run it through the coffee filter - hopefully everything will get trapped - and that will be my magic formula!
Here's my plan:
I'm planning to go borax anyway.
Use the oxalic in concert with borax...
Any disadvantage to using Oxalic vs muriatic with the borax?
I understand that higher PH causes lower CH solubility?
Thus keeping the PH up, would make more precipitate out?
So add them together?
First experiment will be in spa:
Add oxalic until milky.
Add boarx until PH comes back up.
Add clarifier (or floc? which do you think would be best while adding the least extra gunk to my pool)?
I'd rather filter, rather than try to figure out how to "vacuum to waste" becase my pump isn't set up for that.
If that goes good, spillway that water into the pool and repeat (8 or so times).
Should I lower the cl - I saw some reference to that - but I remember something about using cl to oxidise the dangerous calcium oxalate?
Should I ph balance before or after trying to filter?
Is the stuff I'm hoping to filter out dangerous?
Am I crazy (or just an engineer)?
Two comments/topics both in regards to reducing ch in my pebble-tech, swg pool that has impermeable scale on natural stone at waterline.
My CH is 650-750
1. Regarding putting a filter downstream of the SWG to catch the chunks it throws off when reversing...
I've thought about that, but unless you can segregate them from the flow, wouldn't the water circulating around them redissolve them?
I've thought about hanging a mesh bag (one of those stainless dryer lint trap bags) on mine.
Because of my concern that they redissolve I haven't bothered, I just pick them out by hand from the spa or baja when I see big ones.
Say my 20K gallon pool weighs 160K pounds.
If I want to go down 200ppm CH, that's 30 POUNDS of CH I have to remove?
That's gonn'a take an awful lot of little chunks.
2 - Using oxalic acid to precipitate ch.
Regarding not being able to control the scaling, won't any undersired scaling that ends up pool equipment/surfaces eventually redisolve after things go back to normal?
I couldn't help myself from stopping at ACE and picking up two 12oz tubs of "Savogran Wood Bleach" at $9 something each. (90+% pure oxalic according to their msds).
1. Put some distilled water in a glass. Can dissolve quite a bit of oxalic powder in the distilled water (in terms of pinches) before it won't dissolve any more.
Water stays Crystal clear.
2. Add 10% that water to 90% pool water - immediately forms milky precipitate (that did not immediately settle) as desribed in Solarboys recent experiences.
3. Similarly, Add a tiny pinch to 100% pool water, same precipitate.
4. Run these samples through coffee filter (how's that compare to my Pentair cartridges?) and very little (1/4 maybe) was caught.
5. Tested PH (way) below my testers minimum 6.8. (dark yellow, like my cl tester when cl is 5+)
6. Used baking soda (a pinch) to get one glass up to 7.4. No noticeable change in precipitate
(I expected more because I thought solubility of ch was lower at higher ph?)
7. Added a teaspoon or so to half a homedepot (5gal) bucket of pool water.
Got mily precipitate.
Added a couple of drops of the blue liquid clarifier to a glass of water, stirred and added to 2.5gal in bucket.
8. Finally, I had my first experimental glass where I had added the distilled/oxalic mixture to pool water and was all milky.
I poured it out, and as Chem Geek predicted, the glass was awful.
All dingy with a film of "water spots". It wiped off easily with my finger, but I left it.
I filled the glass with pool water and we'll see if it redisovles.
Hopefully when I get up tomorrow:
1. Glass with 10% distilled/oxalic to 90% pool - precipitate settled as fine dust..
2. Glass with oxalic, pool, baking soda - greater amount of precipitate settled as fine dust.
3. HD bucket with pool water, oxalic and dash of blue clarifier, clumped/coagulated and settled.
Since I can't vacuum to waste, I'll stir some of the bucket up and run it through the coffee filter - hopefully everything will get trapped - and that will be my magic formula!
Here's my plan:
I'm planning to go borax anyway.
Use the oxalic in concert with borax...
Any disadvantage to using Oxalic vs muriatic with the borax?
I understand that higher PH causes lower CH solubility?
Thus keeping the PH up, would make more precipitate out?
So add them together?
First experiment will be in spa:
Add oxalic until milky.
Add boarx until PH comes back up.
Add clarifier (or floc? which do you think would be best while adding the least extra gunk to my pool)?
I'd rather filter, rather than try to figure out how to "vacuum to waste" becase my pump isn't set up for that.
If that goes good, spillway that water into the pool and repeat (8 or so times).
Should I lower the cl - I saw some reference to that - but I remember something about using cl to oxidise the dangerous calcium oxalate?
Should I ph balance before or after trying to filter?
Is the stuff I'm hoping to filter out dangerous?
Am I crazy (or just an engineer)?
If you use oxalic acid, then that will lower the pH significantly. If you use sodium oxalate, then the pH won't change very much at all. Either way, they both reduce chlorine to chloride so during this treatment the chlorine will get to zero. As for CH being less soluble at high pH, that is not true. It is calcium carbonate that is less soluble at higher pH, but not calcium oxalate, at least not at normal pool pH ranges.
Since you are adding borates using 20 Mule Team Borax, you can use oxalic acid instead of Muriatic Acid if you like. The Savogran Wood Bleach is oxalic acid dihydrate. 1 pound of this product is roughly equivalent in acidity to 3 cups of full-strength Muriatic Acid and will eventually precipitate around the same weight of calcium oxalate reducing CH by almost 10 ppm in 10,000 gallons. Note, however, that calcium oxalate is a little soluble in water at around 9 ounces weight per 10,000 gallons so precipitate will only form after that amount has been added. That also means that even if you remove all the precipitate, it will take around 3.7 ppm FC to get rid of the dissolved calcium oxalate (i.e. you won't be able to hold chlorine until at least that much is added). If you have calcium oxalate stuck on walls, then it will take even more chlorine before it holds.
Again, I don't think this is a very controllable method though calcium oxalate is less likely to stay stuck to plaster than calcium carbonate. It will be interesting to see what happens with your experiments. Note that since you want to prevent algae from growing when the chlorine gets to zero, you might consider using Polyquat 60 to prevent algae. It is also a clarifier so that might be helpful as well for what you are trying to do though I don't know how well it will clarify calcium oxalate (and it might not).
Since you are adding borates using 20 Mule Team Borax, you can use oxalic acid instead of Muriatic Acid if you like. The Savogran Wood Bleach is oxalic acid dihydrate. 1 pound of this product is roughly equivalent in acidity to 3 cups of full-strength Muriatic Acid and will eventually precipitate around the same weight of calcium oxalate reducing CH by almost 10 ppm in 10,000 gallons. Note, however, that calcium oxalate is a little soluble in water at around 9 ounces weight per 10,000 gallons so precipitate will only form after that amount has been added. That also means that even if you remove all the precipitate, it will take around 3.7 ppm FC to get rid of the dissolved calcium oxalate (i.e. you won't be able to hold chlorine until at least that much is added). If you have calcium oxalate stuck on walls, then it will take even more chlorine before it holds.
Again, I don't think this is a very controllable method though calcium oxalate is less likely to stay stuck to plaster than calcium carbonate. It will be interesting to see what happens with your experiments. Note that since you want to prevent algae from growing when the chlorine gets to zero, you might consider using Polyquat 60 to prevent algae. It is also a clarifier so that might be helpful as well for what you are trying to do though I don't know how well it will clarify calcium oxalate (and it might not).
- Jan 26, 2011
- 40
Rickster, nice to have someone else looking into this.
Using chem geek's suggestion, I finally determined that my CH is around 900. The results of my experiments with small amounts of water are that the calcium oxalate is difficult to get rid of. Just like Rickster I could only filter about 25% of the stuff out with a coffee filter and it lowered the ph just like anyone would expect. And, chem geek was also right about how sticky this stuff is. It grabs onto surfaces and clings. An overnight wait on around 25ml of the combined pool water and precipitate left a mostly clear tube with fine powder on the bottom. Not sure if that fine dust would vacuum or if it would just circle around the vacuum head though.
However, it doesn't seem to hang on like the carbonate or sulfate. Both of those form the rocks we have all come to know and love while the oxalate is a fine dust that seems to just cling, not become a new pool fixture.
No matter what I tried I couldn't get the oxalate to re-dissolve into the water. It appears the various articles are correct in that this stuff is almost insoluble.
Here's the problem I suspect. We get the precipitate and filter some of it out, then we put back chlorine to keep the pool from going green and it wipes out the oxalate putting the Ca back into the pool. We gain some lowering of the CH, but not much because we couldn't filter all the precipitate out. So, what do we know about flocculants? Maybe we could dissolve the oxalic acid in water and pour it into the skimmer letting the precipitate get caught mostly in the filter. Filter for a day and then clean the filters??
One thing that chem geek said kind of bothers me. If we can only get rid of roughly equal weight of the calcium carbonate and a pound of oxalic will only give us 10ppm reduction. So, to go from 900 down to 250 or so would be a whole lot of pounds. Chem geek, did I hear you correctly??
I'm also using oxalic acid, Sodium oxalate wasn't available, and I didn't think about getting some wood bleach. Good catch.
Using chem geek's suggestion, I finally determined that my CH is around 900. The results of my experiments with small amounts of water are that the calcium oxalate is difficult to get rid of. Just like Rickster I could only filter about 25% of the stuff out with a coffee filter and it lowered the ph just like anyone would expect. And, chem geek was also right about how sticky this stuff is. It grabs onto surfaces and clings. An overnight wait on around 25ml of the combined pool water and precipitate left a mostly clear tube with fine powder on the bottom. Not sure if that fine dust would vacuum or if it would just circle around the vacuum head though.
However, it doesn't seem to hang on like the carbonate or sulfate. Both of those form the rocks we have all come to know and love while the oxalate is a fine dust that seems to just cling, not become a new pool fixture.
No matter what I tried I couldn't get the oxalate to re-dissolve into the water. It appears the various articles are correct in that this stuff is almost insoluble.
Here's the problem I suspect. We get the precipitate and filter some of it out, then we put back chlorine to keep the pool from going green and it wipes out the oxalate putting the Ca back into the pool. We gain some lowering of the CH, but not much because we couldn't filter all the precipitate out. So, what do we know about flocculants? Maybe we could dissolve the oxalic acid in water and pour it into the skimmer letting the precipitate get caught mostly in the filter. Filter for a day and then clean the filters??
One thing that chem geek said kind of bothers me. If we can only get rid of roughly equal weight of the calcium carbonate and a pound of oxalic will only give us 10ppm reduction. So, to go from 900 down to 250 or so would be a whole lot of pounds. Chem geek, did I hear you correctly??
I'm also using oxalic acid, Sodium oxalate wasn't available, and I didn't think about getting some wood bleach. Good catch.
If you get reverse osmosis, it will remove calcium and sulfate. Then you could use a water softener to remove calcium from your fill water to prevent calcium buildup. You're actually lucky that you're in an area that the reverse osmosis service is available, as most people do not have this option.
What is your sulfate level?
What is your sulfate level?
A pound reduces "CH by almost 10 ppm in 10,000 gallons"?
Oops there goes my plan.
After seeing the "drifts" in solarboys pics after adding "a few ounces" of oxalic, it looked like many, many pounds of CH.
In 20K gallons, I'd need an awful lot of oxalic acid (80 Lbs? at $9 (retail)/lb) and lots of work to reduce by 400ppm...
Hiring the reverse osmosis dudes is starting to look appealing. Though they never returned my email
Though I'd need to re-salt and cya, maybe about $180 in chemicals...
But that wouldn't require any "work", nor risk scaling my walls and pipes.
Oops there goes my plan.
After seeing the "drifts" in solarboys pics after adding "a few ounces" of oxalic, it looked like many, many pounds of CH.
In 20K gallons, I'd need an awful lot of oxalic acid (80 Lbs? at $9 (retail)/lb) and lots of work to reduce by 400ppm...
Hiring the reverse osmosis dudes is starting to look appealing. Though they never returned my email
Though I'd need to re-salt and cya, maybe about $180 in chemicals...
But that wouldn't require any "work", nor risk scaling my walls and pipes.
draythomp said:
I don't think this is a good idea.
The PH seemed extremely low.
I don't think we want that running through the plumbing?
And I don't think clarifiers/floculants work fast enough to get the precipitate on the first pass.
I was thinking of lining my spa with a plastic dropcloth and using it as a processing plant, but I want to get 400ppm out of the pool...
- Jan 26, 2011
- 40
My CH level is around 900; I can't tell exactly because I cut the test back to 10ml so I only get 25ppm resolution so it could be from 875 to 925 or so.
Like I said before, I can't find out how much reverse osmosis costs; the company hasn't called me back yet. Additionally, their add says that they use up 20% of the water in the pool during the process so it would take a truckload of water to replace what they use up. I'm on a well and can't pull that kind of volume in a short amount of time here in the desert. The water delivery trucks will only hang around for an hour, so I would have to rent a tank to store the water in during the process and probably a pump to get it from the tank to the RO trailer. So, $150 for tank, $45 for pump, $100 for water delivery, peak power usage costs for electricity for the truck would depend on how large the pump inside the truck is but would probably raise my power bill by $70 for the month (peak demand billing). This is probably a worst case scenario, but my experiences have mostly been worst case, so I plan for it.
The idea of using my water softener to fill the pool is compelling except for the modifications to get water there. The pool is surrounded by a concrete patio and the fill device is fed under that from the house slab. When I built the house I had the plumber run the outdoor faucets separately from the indoor faucets to keep from watering the plants from the water softener and the pool people hooked up to that water system. I really don't want to cut the patio to get a pipe out there.
I mean, there are things I can do like add another water softener that uses salt just for the pool and install another fill device plumbed to it. That would probably increase my salt level over time, but that would have to be seen. I could probably put in a water softener and feed it from the pool water to soften it directly; actually, that doesn't sound like too bad an idea. Just use the pool pump to provide water to the softener and feed the output right back into the pool. Hmmm, regeneration would have to be considered carefully and where I dispose of the waste water could be a concern (I have a septic tank).
But until I get a call back from the pool RO company, I won't have a reasonable handle on the various costs. So, I'm looking at using chemical warfare to develop a technique for Ca removal.
Like I said before, I can't find out how much reverse osmosis costs; the company hasn't called me back yet. Additionally, their add says that they use up 20% of the water in the pool during the process so it would take a truckload of water to replace what they use up. I'm on a well and can't pull that kind of volume in a short amount of time here in the desert. The water delivery trucks will only hang around for an hour, so I would have to rent a tank to store the water in during the process and probably a pump to get it from the tank to the RO trailer. So, $150 for tank, $45 for pump, $100 for water delivery, peak power usage costs for electricity for the truck would depend on how large the pump inside the truck is but would probably raise my power bill by $70 for the month (peak demand billing). This is probably a worst case scenario, but my experiences have mostly been worst case, so I plan for it.
The idea of using my water softener to fill the pool is compelling except for the modifications to get water there. The pool is surrounded by a concrete patio and the fill device is fed under that from the house slab. When I built the house I had the plumber run the outdoor faucets separately from the indoor faucets to keep from watering the plants from the water softener and the pool people hooked up to that water system. I really don't want to cut the patio to get a pipe out there.
I mean, there are things I can do like add another water softener that uses salt just for the pool and install another fill device plumbed to it. That would probably increase my salt level over time, but that would have to be seen. I could probably put in a water softener and feed it from the pool water to soften it directly; actually, that doesn't sound like too bad an idea. Just use the pool pump to provide water to the softener and feed the output right back into the pool. Hmmm, regeneration would have to be considered carefully and where I dispose of the waste water could be a concern (I have a septic tank).
But until I get a call back from the pool RO company, I won't have a reasonable handle on the various costs. So, I'm looking at using chemical warfare to develop a technique for Ca removal.
- Jan 26, 2011
- 40
Rickster, I'm not concerned about the high acid level, everything I have is plastic or pebble tech and the low ph would only be for the period of time before whatever I add to take it back up works. Could have a little trouble with the cartridge filter elements though and those darn things cost a ton to replace.
However, the low reduction levels are a disappointment. That water softener idea is getting more compelling all the time.
However, the low reduction levels are a disappointment. That water softener idea is getting more compelling all the time.
- Jan 26, 2011
- 40
OK, so I'm driving everyone nuts with this.....sorry.
I just spent some time looking at the water softener idea. Suppose I plumb in a line to the pool system and take water after the filter and before the pool and run a 1" into a water softener so that some of the pool water is treated and returned to the pool. These things can reduce the Ca by a whole lot more than we're looking at chemically. Initially I might have to regenerate it every other day, but over time, this should work.
Costs are not totally out of reason, should be able to get one for around $500 and then maybe $50 or so in plumbing parts to hook it up. I'd have to somehow cover it from the weather and probably run it during the few days a year when the temperature goes to freezing, but that's manageable. It may even be possible to turn it off once I get the Ca level down to something more reasonable.
Give me some thoughts about this idea.
I just spent some time looking at the water softener idea. Suppose I plumb in a line to the pool system and take water after the filter and before the pool and run a 1" into a water softener so that some of the pool water is treated and returned to the pool. These things can reduce the Ca by a whole lot more than we're looking at chemically. Initially I might have to regenerate it every other day, but over time, this should work.
Costs are not totally out of reason, should be able to get one for around $500 and then maybe $50 or so in plumbing parts to hook it up. I'd have to somehow cover it from the weather and probably run it during the few days a year when the temperature goes to freezing, but that's manageable. It may even be possible to turn it off once I get the Ca level down to something more reasonable.
Give me some thoughts about this idea.
- Jan 26, 2011
- 40
I outran all of you. You poor people that have to work during the day..
The RO guy called back. He will charge me $500 for the treatment and that includes rebalancing the water when he's done. It will take about 2000 gallons of water so I can have the local water delivery company come out about half way through the process and deliver enough water to refill my well tank for $60. The RO machine he uses has its own generator so there are no power costs at all, but I have to pay a $25 surcharge to cover the extra fuel costs for living in the middle of nowhere. I'm looking at less than $600 bucks to get the pool taken down to lower Ca levels than I started with. Then I have to figure out how to hook the pool to the water softener to keep it from happening again.
This looks like the solution to my problem.
So, JamesW, you earned it. Go ahead and say, "I told you so." .....
The RO guy called back. He will charge me $500 for the treatment and that includes rebalancing the water when he's done. It will take about 2000 gallons of water so I can have the local water delivery company come out about half way through the process and deliver enough water to refill my well tank for $60. The RO machine he uses has its own generator so there are no power costs at all, but I have to pay a $25 surcharge to cover the extra fuel costs for living in the middle of nowhere. I'm looking at less than $600 bucks to get the pool taken down to lower Ca levels than I started with. Then I have to figure out how to hook the pool to the water softener to keep it from happening again.
This looks like the solution to my problem.
So, JamesW, you earned it. Go ahead and say, "I told you so." .....
A flocculant such as OMNI Liquid Floc Plus might work better for this situation than a clarifier, but I'm not sure and you'd have to experiment to find out.draythomp said:
As for the one pound of oxalic acid dihydrate lowering CH by 10 ppm in 10,000 gallons, that is correct. If someone wants to check my math, I got this from the following: (1 pound) * (453592 mg/pound) * (100 g/mole calcium carbonate) / (128 g/mole calcium oxalate) / (37854 liters) = 9.4 ppm. I assume the precipitate is calcium oxalate anhydrous though it could be the monohydrate at 146 g/mole.
As for using water softeners, the main problem there is the volume of water and amount of regeneration needed. It's certainly doable, but for any of these solutions including reverse osmosis you have to look at total cost and it's not going to be cheap no matter which way you go. Hard water is, well, hard to get rid of!
I'm glad the RO guy got back with a decent quote. Where that's available, it's certainly a straightforward and proven solution. A water softener is then reasonable for treating fill water.
- Jan 26, 2011
- 40
Your math checks out. I had some trouble realizing where the 453592 came from. But, it should have been obvious to me; molecule in, molecule out. I guess I was mostly hoping for a solution that didn't require hiring someone and the incompetence risks that entails. However, I know a heck of a lot about testing the water now and have the equipment so I can see for myself exactly where it is when the process is finished. So, risk minimized.
- Jan 26, 2011
- 40
OK, the reverse osmosis guy has come and gone. It was an interesting experience. I live out in the sticks and use well water so here's what I did.
The guy came out about 14:00 and set up his machine. My TDS was up around 4000 and I think my CH was 1000 or so. Difficult to tell that high. The machine had a pool pump at the end of a hose setting next to the pool with a 2 inch pipe into the pool about 3 feet; the hose led into his enclosed trailer. Coming out of the trailer was another 2 inch hose that he set at the opposite end of the pool along with two of those portable float refiller things that hooked to the well. He assured me that the filler I had wouldn't keep up and that the others were necessary. Trust me, they were. There was also a waste water hose that we ran over to a wash on my property and let run into the neighbors yard. I went over and told the neighbor so he wouldn't be concerned, and since it was a natural wash, he didn't care at all. We both hoped the water would kill some of the weeds that sprout out there from time to time.
I had 2000 gallons of water scheduled to be delivered at 18:00, but the company forgot and it was 20:30 before they showed up. I had turned off the refill devices (all of them, his and mine) so my pool level had dropped around 2 feet and it took the entire 2000 gallons to fill it up to the brim. I wanted to get all the water I could into the pool to lessen the impact on my well pump.
I turned on the fill devices, and after watching it a while, went to bed. 06:00 the next morning I checked the level. Even with the three fill devices, the pool level had dropped 8 inches so I turned on a water hose to supplement them. Over time, the hose overcame the drop and the pool came to its normal level. I over filled it about 2 inches and turned off the hose.
He arrived around 14:30 and shut the machine down. My CH was 150 and the TDS was around 900 with 450 of that being salt. So, I managed to save some of the salt and got rid of almost all of the Ca. :lol: I was wrong (wishful thinking) about him supplying the start up chemicals, so off to the store for CYA and salt I went. I'm in the process of balancing out the pool right now and should be good to go in another day or two.
Cost? The machine cost me $500 because I had to pay a surcharge for distance. Remember, I live in the sticks and gas costs money, so I didn't (much) mind the $50 bucks extra. Especially since his machine has it's own generator and he didn't plug into my house at all. The 2000 gallons of water cost me $60 and then the usual for the chemicals. Not too bad a difference from just draining some and refilling it: 5 trucks at $60 for $300 and I would have had a CH of over 400 starting out since that is what the water here is.
No, I'm not going to raise my CH up to normal levels; that will happen on its own over time, and there was an unexpected side effect. The lower CH has softened the scale on the side of the pool. Let me restate that, THE LOWER CH HAS SOFTENED THE SCALE ON THE SIDE OF THE POOL. I went around the pool with a power washer and about 80 percent of it came off and is now setting on the bottom of the pool. I just adjusted the pool level up an inch and a half to cover the remaining scale and plan on hitting it again in a couple of days. Then I'll just go around the tile with a scraper and see if I can get the remaining stuff.
Wow.
My salt level is 3200 and as usual, the stupid chlorine generator is showing 2700 so I'm going to push the level up about 300 more before I quit adding salt. I'll measure the CH after the experiment with the scale, I suspect a lot of it will dissolve back into the pool water to haunt me later.
Questions, comments, curses?
PS - There was another unexpected side affect. The waste water caused a big mud puddle and the javalina must have smelled the water. I woke up to a pig party in the mud hole. They were rolling around grunting and playing and stayed until around 10:00 having fun. Nice to have the neighbors drop in for dip once in a while.
The guy came out about 14:00 and set up his machine. My TDS was up around 4000 and I think my CH was 1000 or so. Difficult to tell that high. The machine had a pool pump at the end of a hose setting next to the pool with a 2 inch pipe into the pool about 3 feet; the hose led into his enclosed trailer. Coming out of the trailer was another 2 inch hose that he set at the opposite end of the pool along with two of those portable float refiller things that hooked to the well. He assured me that the filler I had wouldn't keep up and that the others were necessary. Trust me, they were. There was also a waste water hose that we ran over to a wash on my property and let run into the neighbors yard.
I went over and told the neighbor so he wouldn't be concerned, and since it was a natural wash, he didn't care at all. We both hoped the water would kill some of the weeds that sprout out there from time to time.I had 2000 gallons of water scheduled to be delivered at 18:00, but the company forgot and it was 20:30 before they showed up. I had turned off the refill devices (all of them, his and mine) so my pool level had dropped around 2 feet and it took the entire 2000 gallons to fill it up to the brim. I wanted to get all the water I could into the pool to lessen the impact on my well pump.
I turned on the fill devices, and after watching it a while, went to bed. 06:00 the next morning I checked the level. Even with the three fill devices, the pool level had dropped 8 inches so I turned on a water hose to supplement them. Over time, the hose overcame the drop and the pool came to its normal level. I over filled it about 2 inches and turned off the hose.
He arrived around 14:30 and shut the machine down. My CH was 150 and the TDS was around 900 with 450 of that being salt. So, I managed to save some of the salt and got rid of almost all of the Ca. :lol: I was wrong (wishful thinking) about him supplying the start up chemicals, so off to the store for CYA and salt I went. I'm in the process of balancing out the pool right now and should be good to go in another day or two.
Cost? The machine cost me $500 because I had to pay a surcharge for distance. Remember, I live in the sticks and gas costs money, so I didn't (much) mind the $50 bucks extra. Especially since his machine has it's own generator and he didn't plug into my house at all. The 2000 gallons of water cost me $60 and then the usual for the chemicals. Not too bad a difference from just draining some and refilling it: 5 trucks at $60 for $300 and I would have had a CH of over 400 starting out since that is what the water here is.
No, I'm not going to raise my CH up to normal levels; that will happen on its own over time, and there was an unexpected side effect. The lower CH has softened the scale on the side of the pool. Let me restate that, THE LOWER CH HAS SOFTENED THE SCALE ON THE SIDE OF THE POOL. I went around the pool with a power washer and about 80 percent of it came off and is now setting on the bottom of the pool. I just adjusted the pool level up an inch and a half to cover the remaining scale and plan on hitting it again in a couple of days. Then I'll just go around the tile with a scraper and see if I can get the remaining stuff.
Wow.
My salt level is 3200 and as usual, the stupid chlorine generator is showing 2700 so I'm going to push the level up about 300 more before I quit adding salt. I'll measure the CH after the experiment with the scale, I suspect a lot of it will dissolve back into the pool water to haunt me later.
Questions, comments, curses?
PS - There was another unexpected side affect. The waste water caused a big mud puddle and the javalina must have smelled the water. I woke up to a pig party in the mud hole. They were rolling around grunting and playing and stayed until around 10:00 having fun. Nice to have the neighbors drop in for dip once in a while.
draythomp said:
I know you solved your problem with the RO people, and I may also, but I'm still considering a water softener solution.
Questions for the very helpful chemists:
-I'm thinking of (re)circulating the pool water through a softener.
-Would a water softener work with the salt water in a SWG pool, or will it kill the ion exchange?
-Will the chlorine kill the softener (I've seen "chlorine resistant" resin).
-Will sodium buildup be a problem? Will it magically combine with chlorine to form salt :?
- Running salty water through a standard water softener (Strong Acid Cation, SAC, ion exchange resin) will not be as effective. It will still remove some calcium, but not nearly as efficiently and it will saturate and require recharging more frequently (you would need a more concentrated salt solution during regeneration to get more capacity and reduce calcium leakage). There are Weak Acid Cation (WAC) resins designed to work with high salt waters, but they require hydrochloric acid and then sodium hydroxide for regeneration.RickstersPool said:
- The chlorine should not be a problem for the resin since most tap water is chlorinated and without CYA in the water tap water is far stronger in active chlorine level.
- The exchange of calcium for sodium should not be a big deal. Every 10 ppm of CH reduction will result in 11.7 ppm salt.
- Jan 26, 2011
- 40
When I was looking into the water softener idea I kept running into problems with it. If the pool already has a high level of Ca, it will load the water softener up very quickly. Since these things work on volume and not the actual load, they will stop working until the next regen. If you regen every night, you stand a chance, but the water wasted would be pretty high.
If you use it for fill water (my current plan) depending on the evaporation rate, you could have trouble in peak sunny periods when the water demand of the pool exceeds the capacity of the water softener. That shouldn't be too much of a problem though since there's not many days that will exceed the capacity of the softener.
My neighbors all drain 1/3 of the pool and replace it with trucked-in water a couple of times a year to keep the calcium down. Notably, they all use pool services to take care of the pool for them. Now that I have the Ca level down to below the recommended minimum, I intend to reroute my fill plumbing to the house water softener and keep it down that way. If it starts to get high again, I'll call the guy back or do the 1/3 replacement.
Or, I may look into a high volume reverse osmosis device. The problem with them is that to get the higher volumes, they require higher pressure, in the range of 80 psi. For me that would mean a booster pump and pressure tank. Looking at it from a purely monetary perspective, the reverse osmosis truck is the cheapest option because I don't have to maintain the truck, just call it out every couple of years. The problem I see with that solution is that the competition the truck has is related to the expense of refilling the pool. He can't charge much more than a refill or he won't get business. If his expenses exceed what he can charge, he'll get out of the business and I'll be stuck with a water change as the only cost effective solution.
As a wise forum member once said, "Hard water is hard."
If you use it for fill water (my current plan) depending on the evaporation rate, you could have trouble in peak sunny periods when the water demand of the pool exceeds the capacity of the water softener. That shouldn't be too much of a problem though since there's not many days that will exceed the capacity of the softener.
My neighbors all drain 1/3 of the pool and replace it with trucked-in water a couple of times a year to keep the calcium down. Notably, they all use pool services to take care of the pool for them. Now that I have the Ca level down to below the recommended minimum, I intend to reroute my fill plumbing to the house water softener and keep it down that way. If it starts to get high again, I'll call the guy back or do the 1/3 replacement.
Or, I may look into a high volume reverse osmosis device. The problem with them is that to get the higher volumes, they require higher pressure, in the range of 80 psi. For me that would mean a booster pump and pressure tank. Looking at it from a purely monetary perspective, the reverse osmosis truck is the cheapest option because I don't have to maintain the truck, just call it out every couple of years. The problem I see with that solution is that the competition the truck has is related to the expense of refilling the pool. He can't charge much more than a refill or he won't get business. If his expenses exceed what he can charge, he'll get out of the business and I'll be stuck with a water change as the only cost effective solution.
As a wise forum member once said, "Hard water is hard."