Question regarding dissolved solids

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Z

Zindar

0
Jun 4, 2011
209
Austin, Texas
Hello, I just bought a new above ground vinyl liner pool. (Circular, 18' diameter, about 7600 gallons.)

A thought just occurred to me that I should have researched before buying this pool, but too late now, I guess. My last pool was an in-ground pool, and my water supply was City of Austin, which has decent water. Over the years dissolved solids got kind of high, and Leslie's Pool Supply told me soon I might consider draining part of the water and replacing. Thankfully it never got to the point where I had to do that. I've since sold that house and pool.

Well, now I live just outside the city limits, and I get my water from a municipality called Brushy Creek M.U.D., and their water has more hardness than City of Austin water, and now I have a brand-new above ground pool. Does harder water mean I could develop a "total dissolved solids" problem sooner than if I had City of Austin water? I would hate to deal with the expense of replacing my pool water periodically.

I looked up my municipality's website, and they say "The latest laboratory report indicated that the hardness of the District's water is 180 milligrams per liter or approximately 10.51 grains". How hard a reading do you people think that is? Does this water sound okay for maintaining a swimming pool?

Now, I should also mention this: We are in stage 2 drought conditions, so I wasn't allowed to fill my pool with district water, so I wound up paying a bulk water supply company $345 to truck in my water and fill my pool. They used City of Austin water to do this, so maybe that's good: I got nonhard water to fill my pool. But over time I think as water evaporates, I'll be replacing it with district water. (I'm allowed to use my district's water for maintenance, just not filling a pool from scratch.)

Another thought I have is that I do have a water softener, so a thought is that I use my softened water to replace evaporated / splashed water, but I don't know an easy way to do that, because my outdoor faucets are unsoftened - only my indoor faucets have access to softened water. Is this something worth looking into (i.e. somehow harvesting my softened water)?
 
Welcome to TFP!

Ignore TDS. It's a pool store term which really means "we don't understand water chemistry". Your hardness could become an issue.
 
Ok, first of TDS or total dissolved solids is a meaningless measurement for pools, or at least it is these days when we have separate tests for the major important components of TDS, anyone giving pool advice based on a TDS report should be looked at the way you should look at a doctor that advises blood letting by leaches. As to the hardness on the report does it specify calcium hardness or total hardness, either way I would not worry about it with a vinyl pool as long as your keep your pH in line.

Ike
 
For some reason, I was only able to look at a summary of the report, but there is a detailed report that has all the various water readings, but the website that hosts it isn't working right now. Tomorrow, I'll call them on the phone and ask to see this detailed report, then I can report the findings back to this thread.
 
Something very annoying happened. Yesterday I wanted to add a little extra water to my pool to make it easier on the pump, so more would go into the skimmer, and when I turned off the hose, I neglected to remove the tip of the hose from the pool. Overnight, some of the water siphoned automatically backwards through the hose, and where the hose connects to the hose bib is where it leaked out. I may roughly estimate that I lost about 500 gallons of my 7600 gallon pool. :mad:

And I had just paid $345 to have good quality city water trucked in, and now I've had to replace it with with my own water. :mad:
Well, I found the water quality report, by the way:

Code: 
Barium				.0353 - 0.0506 ppm
Flouride			.57 ppm
Nitrate				.304 - 1.02 ppm
Dibromochlormethane		13.62   ppb
Chloroform			3.91 ppb
Bromoform			8.69 ppb
Bromodichloromethane		9.3 ppb
Chloramines			2.07 ppm
Haloacetic Acids		12.1 - 19.6 ppb
Total Trihalomethanes		29.3 - 41.0 ppb
Bicarbonate			183 ppm
Calcium				61.7 ppm
Choride				48 ppm
Magnesium			16.8 ppm
Manganese			.00251 ppm
Sodium				28.4 ppm
Sulfate				27.4 ppm
Total Alalinity as CaCO3	183 ppm
Total Dissolved Solids		333 ppm
Total Hardness as CaCO3		182 ppm
pH 				7.7
Conductivity			507 UMH/CM

This is the water report of the water that's delivered to my house from my municipality, and what should be coming out of my hose bib.
 
Both TA and CH are a little high. That won't be a problem in the short run, but as water evaporates and you top off the pool the CH level will tend to go up, eventually getting to a level where you need to pay attention to it.
 

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Darn; if I remember correctly, there's no easy way to lower calcium hardness; I think some people drain their pool when that happens. That makes me even more annoyed that I accidentally siphoned off 500 gallons of my pool last night (about 6.5% of my water).

Question: if my pool were 100% filled with the above water quality, would the calcium hardness be low enough? Also, does it matter more, or matter less, that I have a vinyl pool when it comes to calcium hardness?
 
At time of fill it would be fine, but over time water evaporates and leaves calcium behind. This may or may not be an issue for you depending on where you live, this is part of why we ask people to put their location in their profile. Since rain water contains no CH, it is mostly a question of do you get more rain or more evaporation where you live, so the answer would be different for someone in AZ with hot dry evaporation prone air than someone here in Louisiana where we measure annual rainfall in feet.

Ike
 
When you first fill the pool the CH level will be just fine. There won't be a problem for some time. Slowly, as water evaporates and you then top off the pool, the CH level will go up. CH can more than double before this is a problem, but eventually it will get high enough that you will want to replace most of the water.

Vinyl pools are not bothered by low CH levels, but have the same troubles with high CH levels that all other pools have.
 
Zindar said:
Darn; if I remember correctly, there's no easy way to lower calcium hardness; I think some people drain their pool when that happens. That makes me even more annoyed that I accidentally siphoned off 500 gallons of my pool last night (about 6.5% of my water).

Question: if my pool were 100% filled with the above water quality, would the calcium hardness be low enough? Also, does it matter more, or matter less, that I have a vinyl pool when it comes to calcium hardness?
Click to expand...
From the looks of it, a fresh fill will leave you with 183 CH. And then it will slowly creep up. You can slow the rise by not using Cal-hypo "shock" every week the way the pool store suggests. You won't need to anyway, if you follow our methods, but many people just can't cut the apron strings and shrug off the pool store's dire warnings and canned responses.

Low CH will not harm a vinyl pool. Not that your fill water is low anyway...

High CH can still cause scaling. But I can assure you, it's manageable up to 800; you just don't have so much wiggle room on TA and pH. Come back and ask for solutions when CH hits 600.
 
I note that your tap water has chloramines. This is a combination of chlorine and ammonia which is a more stable form of chlorine that many municipal districts are switching to. (I used to hate to hear that for fish keepers as adding tap water then simply removing the chlorine left ammonia which THEN killed the fish.)

For a pool this means that when you add tap water, you may see a small effect in the CC measurement and also that until that small bit of ammonia is done away with (by more chlorine) you will use a bit more chlorine that you expect. Other than that, the TA of 183 means that you will need Muriatic Acid from time to time to keep pH in line until the TA declines to a point that lets pH stay more level. You will also of course need chlorine in some form, never cal-hypo, for as was mentioned, that CH will go upwards from here, no need to add to it with cal-hypo. Not important until it is really high and the TA is high and scale might form (even in vinyl pool). But, that will be something to watch much later on, not now.

Now, as for the siphoning of that bought water, remember that when it is time to get some water out of the pool. Best to have an empty hose and draw one breath out of the end of it to get the water up over the edge of the pool, gravity will do the rest once the hose is full over the edge, as you see.
 
You've got it easy. My fill water TA is 267 ppm and CH is 367 ppm. Plus we are in drought conditions so I couldn't replace the water this year and I started the season with a CH over 600 ppm. Just watch your CSI and keep it slightly on the negative side (-0.5). This should help: Pool Math
 
Thanks for all this education. The day after the pool was built, I bought over $160 worth of stuff from the pool store, but now I wish I'd come here first. I think after I use up the chemicals I bought I should switch to the methods advertised here, regarding the test kits, and liquid chlorine, and stuff. Not that all the stuff I bought is that bad.. for example I think something like $60 of it was proteam Supreme, which I read on your site as being a good product.

I'm also happy to read you tell me that even a fresh fill gives me a fair amount of growth room for CH, so worst case scenario if CH gets too high down the road, refilling from my garden hose is a viable option. Or this rainwater collection I just read about on your site sounds very interesting too.

To answer the rain/evaporation question: We supposedly get 32 inches a year, but it seems like it's been a long time since we really got that much. I don't know how much evaporation we get, but it seems like in my last pool, I must have added a inch a week from my hose during the summer. I did get a build up of calcium too. I don't think I've ever used the type of shock that has calcium, so I don't think that should have added calcium, so maybe it was from the adding of tap water. Maybe we do get more evaporation than rain. Well, especially the last several years, as they've been drought years.

The other thing to consider is that Austin rain is not smoothly distributed through the year.

1) Maybe once every year or two, we get a rain so heavy it overflows the top of my pool, so that means not all the inches of rain make it into the pool
2) In the past, I've kept a cover over the pool during the winter to keep debris out, and the water warmer, so that could have also blocked rain from getting in. I'm inclined not to do that for my current pool though. (Editted... no I don't see how the cover would have blocked the rain, on second thought. It'd've just flowed across to the edges of the cover and still gotten in.)
 
We have some members in drought areas with high CH that catch rainwater from their gutters and direct it to the pool by way of a bit of filtration. In your area the composition of west texas dust may effect your pool water.
 
anonapersona said:
I note that your tap water has chloramines. This is a combination of chlorine and ammonia which is a more stable form of chlorine that many municipal districts are switching to. (I used to hate to hear that for fish keepers as adding tap water then simply removing the chlorine left ammonia which THEN killed the fish.)

For a pool this means that when you add tap water, you may see a small effect in the CC measurement and also that until that small bit of ammonia is done away with (by more chlorine) you will use a bit more chlorine that you expect.
Click to expand...
Note that those concentrations are in ppb, parts per billion. Very low and not likely to measure for the purposes of pool testing. They will also dissipate very quickly when exposed to sun and aeration. The reason indoor faucets have small screens is to aerate water as it comes out, helping to eliminate these disinfection by-products.


Sent from my SCH-I545 using Tapatalk
 
Ahh, Austin. IIRC you pretty much get the entire year's rain in a couple of days.

Last time I was down there and it rained everyone ran out of meetings to watch :D

I don't know how predictable the torrential rains are but if your CH is creeping up (or if you get your CYA too high from using stabilized chlorine from the pool store) it's probably worth draining the pool down a bit to make room for the nice clean rainwater.
 

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