SWG + Hard water fustrations

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RicknTX

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Jul 11, 2011
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Hi,

I've been reading through the forums here to get an understanding on things and I feel a little lost in how to battle my hard water issues. We live in South Central Texas where the temps usually rest at 100+ degrees daily here and the upper 70s-80s at night.

The water is extremely hard here and I know it causes Calcium buildup on the SWG, but according to what I read it is supposed to go at least a few weeks before I have to get out the vinegar and get to cleaning again. My results have been anything but and I've been having to clean the SWG cell at least every few days which is very time consuming and frustrating to say the least.

Last week I spent several days putting in Muratic Acid trying to get the PH and Acid levels under control on the advice from a friend who has a pool. He told me I needed to get the acidity under control before I could tackle the PH as it would be a waste of time. I also know that the PH is being controlled by the hard water too..

Without being able to keep the SWG working consistently, my chlorine levels fall and remain near non-existent because of the calcium build ups..

I took my reading tonight after shocking my pool on Friday night with 2 lbs of Dichlor, but as expected things are starting to fall apart again..

Does anyone out there have any advise on how I could get the hard water / calcium under grips? Is it true that I need to do this *first* before I can get the rest working properly?? I feel like for every 2 steps I take, I look 4 steps 24-48 hrs later.. The pool is staying very clear and clean, but the chemical tests show that there is a hidden problem..

Readings tonight:
Copper - 0.1
PH - 8.4 (could be higher that is the top of the scale on the tests)
TA - 210
FC - 0-1
CYA - 30-50
Gallons - 6000 (per pool calculator - 16' round x 48")
Salt added initially - 120 lbs (3 bags x 40lb each)
Acid Demand - 3

Water source (Tap water) readings:
PH - 7.2
FC - 2.0 - 3.0
TA - 250

Help!!!!!! Any suggestions are truly welcomed as I'm really at my wits end right now trying to get this right.. I know if I can get this under control, it will be better down the road..

Thanks!!
 
Use the pool calculator to determine how much 31.45 % muriatic acid you need to add to lower the pH from where it is to 7.2. Add the amount of acid and then retest after 1 hour. Continue to lower the pH to 7.2 until the TA is where you want it. Try to get it to about 60 ppm.

What is your calcium hardness level (Not total hardness).

pool-school/lowering%20total%20alkalinity

Also, click on the "Pool School" button and go through the information to get a better understanding of how to manage the chemistry.
 
Quick question..

While I continue to work on this M.Acid being added is it ok to swim in the pool or should we stay out? My daughter and I were in last night and it was fine.. Like I said.. Looking at it, it seems fine, but when you run the tests.. no way!

What about the calcium buildups in the SWG?? Is there anyway to soften the water or with the MAcid be helping to battle that too???

Thank you all again!!
 
Wait about 1 hour after adding the acid and test the pH, as long as it's not less than 7.2, then you're good to swim.

Once you get the TA and pH down, you will reduce or eliminate scaling depending on the Calcium Hardness level.
 
To get control of the scale you need to keep careful control of pH and Total Alkalinity. Keep your pH below 7.6 and TA under 80 and your problem will go away. After you get a grip on that you can look into the benefits of borates, which would make it even easier.
 
Looks like you are on the right track with the Muriatic Acid to work on the PH. You should do some more reading on the relationship between PH, TA and your Calcium Hardness (CH).

A high PH (on the scale of 7.0 - 8.0) and a high TA are going to cause the calcium in your water to percipitate out. This will happen more inside the salt cell because of the reactions taking place in there. That's why you are having such problems.

So lowering your PH to 7.2 will help a lot. Doing this will also begin to bring the TA down.

Remember - your high TA and SWG are both going to contribute to a rising PH which will make the calcium worse as it rises. So testing PH and adjusting with acid should be something you do at least a couple times a week until it settles down.

Since we dont have a CH number for your water we can't say exactly what your goal TA would be - but certainly TA 80 or less.

If you have the CH of your pool post it. Also - the CH and TA of your fill water would shed some light on your situation.
 
Thank you!

I'll go pickup some more muriatic acid tonight after work and get started. I've read conflicting posts in various places that you can only add so much at a time and then again only so much in a given day..

My friend at work was saying he does a quart at a time easily when needed, of course, his pool is an IG and much larger than my 16' x 48".

lightingguy said:
Since we dont have a CH number for your water we can't say exactly what your goal TA would be - but certainly TA 80 or less.

If you have the CH of your pool post it. Also - the CH and TA of your fill water would shed some light on your situat
Click to expand...

Here's my fill water stats that were way back at the original posting:

Readings tonight:
Copper - 0.1
PH - 8.4 (could be higher that is the top of the scale on the tests)
TA - 210
FC - 0-1
CYA - 30-50
Gallons - 6000 (per pool calculator - 16' round x 48")
Salt added initially - 120 lbs (3 bags x 40lb each)
Acid Demand - 3

Water source (Tap water) readings:
PH - 7.2
FC - 2.0 - 3.0
TA - 250
Click to expand...

My drop tester I picked up at Home Depot doesn't have CH.. I'm looking around for one of those Taylor kits that might have that in it per the articles here.. I've located a good Taylor salt tester online since my strips weren't working too well for that.. Should be here in a few days..
 
How much acid is safe to add at one time very much depends on your TA and Borate levels. The higher those are, the more acid you can add safely. One good approach is to use the Pool Calculator to figure out how much acid you need and then try using about 2/3 that much, give it an hour to mix in, test PH again, and continue to adjust from there.

The goal of the "don't add more than X amount of acid per day" rules is to keep the PH within bounds. If you actually measure the PH and do your calculations correctly you can way exceed the normal limits. Just keep the PH between 7.2 and 7.8 and you will be fine even adding lots of acid hourly. The key is testing PH and knowing where you are, so you know when to stop, instead of using some generic guess that may or may not apply in your situation.
 
sorry - missed the fill water TA in your post. Easy to see where that problem comes from.

tftestkits.net is where most of us get our testing equipment. The TF-100 is a great kit at a really good price. I can't recommend it more highly. If you are going to be maintaining your pool yourself the best investments you can make are the good test kit and enough time in pool school until you're proficient.

The big difference between the HD drop tester and the TF-100 or Taylor K2006 is going to be the Free Chlorine test. The better kits are the FAS-DPD chlorine test which is a "count the drops" test as opposed to comparing color. If you ever need to shock your pool being able to test chlorine higher than 5ppm is going to be important.
 

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Hi all,

Things appear to be progressing..

Last night my PH was 8.4+ (off the scale) for my drop testing.. Acid Demand was a 5 which required 2 1/2 Cups of Muriatic Acid.

I did this around dinner and then went back out around 11p last night and did another test.. The PH had dropped slightly and the acid demand dropped to 3. So I put in another Pint or so to give it an overnight stay.

When I got up this morning the PH is 7.6 and TA was still 200 ppm. I did another pint to see if this continues to knock that PH down. My chlorine level is next to zero now, so I'll probably have to shock the pool tonight to fix that since I can't use the SWG until I get the PH and water hardness under control again. The calcium just builds up on the plates too quickly so I'm just running the pump right now to keep the circulation going.

Does this still sound like a good plan??

Hopefully the PH will come down the rest of the way today while I'm at work. I'll have to work on some of the fountain stuff next weekend possibly..

Thanks for all the feedback thus far.. it has been a huge help along with the postings in pool school!!
 
lightingguy said:
sorry - missed the fill water TA in your post. Easy to see where that problem comes from.

tftestkits.net is where most of us get our testing equipment. The TF-100 is a great kit at a really good price. I can't recommend it more highly. If you are going to be maintaining your pool yourself the best investments you can make are the good test kit and enough time in pool school until you're proficient.

The big difference between the HD drop tester and the TF-100 or Taylor K2006 is going to be the Free Chlorine test. The better kits are the FAS-DPD chlorine test which is a "count the drops" test as opposed to comparing color. If you ever need to shock your pool being able to test chlorine higher than 5ppm is going to be important.
Click to expand...

No problem!! I appreciate your responses!!

I've got a K2006 enroute by mail.. should be here by the weekend or Monday at the latest..
 
RobbieH said:
Don't shock the pool. Just add enough liquid chlorine (bleach) to get your FC back into range. Since you have SOME FC there, you probably won't have to shock.

I have the chems to do the acid demand tests also, but prefer to use the pool calculator. Have you given it a shot? http://www.poolcalculator.com
Click to expand...

Hi Robbie,

I actually couldn't get any color in my drop reader this morning for FC. It was clear without any yellow coloring in there at all.

You still think I should just go with bleach?

I actually pulled down the pool calc for my iPhone and have it on there. I've seen the one on the website too.
 
You definitely want to get the Chlorine level up to 5ppm - based on an assumed CYA of 40ppm. Algae can form very quickly in warm water, which is just going to create a second frustrating problem for you. If you find you are loosing more than 2ppm per day in chlorine you might have a small algae bloom now and shocking the pool might not be a bad idea (kill it before it gets going.)

Remember - the chlorine in bleach is the same as the SWG is the same as Trichlor pucks, liquid "shock", cal hypo etc. It's all hydrochlorous acid and should be maintained in proportion to your CYA level to ensure the proper amount of active sanitizer in the pool.

Sounds like a good plan to start on the PH. Getting your PH down isn't going to be an issue - the acid will work very quickly. Getting your TA down might be a bit trickier. The acid will bring the TA down slowly everytime you add it - but your fill water is going to push it back up so you will be fighting yourself.

No way to predict how those 2 opposing forces will work out with time - so just stay on top of the PH and see how well the TA comes down over the next few weeks.
 
lightingguy said:
You definitely want to get the Chlorine level up to 5ppm - based on an assumed CYA of 40ppm. Algae can form very quickly in warm water, which is just going to create a second frustrating problem for you. If you find you are loosing more than 2ppm per day in chlorine you might have a small algae bloom now and shocking the pool might not be a bad idea (kill it before it gets going.)

Remember - the chlorine in bleach is the same as the SWG is the same as Trichlor pucks, liquid "shock", cal hypo etc. It's all hydrochlorous acid and should be maintained in proportion to your CYA level to ensure the proper amount of active sanitizer in the pool.

Sounds like a good plan to start on the PH. Getting your PH down isn't going to be an issue - the acid will work very quickly. Getting your TA down might be a bit trickier. The acid will bring the TA down slowly everytime you add it - but your fill water is going to push it back up so you will be fighting yourself.

No way to predict how those 2 opposing forces will work out with time - so just stay on top of the PH and see how well the TA comes down over the next few weeks.
Click to expand...

The shock I have from Lowes is actually Dichlor.. Any worries with continuing to use that?? It comes in 1 lb sleeves.. I have a few more of those left..
 
Things appear to be getting better.. Although we received our first rain of the summer tonight, so it might mess with things..

Tonights Readings:

FC - Pretty much 0
TA - 180 ppm
PH - 8.0
Acid Demand - only a 3 (1 1/2 Cups)

*Only ones I can test for right now - test strips I have are terrible and read completely differently than my drop tester *
Click to expand...

I went ahead and put in the 1 1/2 Cups even with the rain to keep going. I'll test again tomorrow morning to see what the final results are. No more strong rain chances in the foreseeable future here.. uggh.. We really need it bad..
 
The dichlor you have is ok in the short term because your CYA is lowish for running a SWG. Look at the bottom of pool calculator for the effects of adding chemicals and you can see how much a pound of dichlor will raise the FC and CYA in your pool. You dont want the CYA getting above 80 - even with a SWG.

The higher the CYA in the pool - the higher the FC level should be maintained in order to keep the proper level of active sanitizer in the pool.
 
I have the same frustrations as you are describing. Temps at 100+ here for weeks now and water temp at 94 degrees.
SWG can't keep up with demand, so every morning (or evening), I take a FC reading and add enough clorox to get my
FC to 5 or 6. If the kids remember to run the SWG, it goes for 9 hours a day and FC remains fairly constant.

My TA is way too high mostly due to the fact I am replacing evaporated water with tap water every other day it seems.
I still haven't figured out how to build crook's fountain, so can't aerate enough to get the TA down. With TA so high,
I have to add some times 6 cups of muriatic acid to get my pH down to 7.2, and I do it every time the pH rises to 7.8.
Has my TA budged? Just barely...went from 150 to 130 and right back up when I replaced evaporated water.

I'm hoping once I can figure out how to get the fountain hooked into the thru wall, I can get the pool water temp
down and the TA down so I don't have to keep worrying so much about the pH.

I think you need to concentrate on keeping your FC level up, try to get some additional aeration going, keep
an eye on the pH, and hopefully, your numbers will fall in line. I'm still waiting for my numbers to fall in line,
but we swim as long as the pH is acceptable and the FC is good. I don't worry too much right now about the
TA because there doesn't seem to be much I can do with it until I can figure out how to increase aeration. I
have read a couple of posts where, once they get their fountains going, the TA falls dramatically and the water
temp improves. Good Luck!
 

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