Calcium Hardness

[Ciscokid]

My PH is 7.4 TA= 100 CYA=60 and CH=550 Pool temp is 76. Thanks for all the information.
I was also thinking of raising the borates to help with the stabilization of the PH in my pool. I found this in another post.It was very interesting and seems like it will help my situation.

[chem geek]

Well, your saturation index is now +0.06 or essentially perfect. When your CH was at 200, it was -0.32 which is slightly corrosive, but not so much as to cause the CH to rise as you saw it UNLESS the addition of acid kept the pH much lower or the acid pouring corroded the plaster where you poured, but this seems like a stretch. So this is a mystery unless someone figures it out.

Anyway, your pool is in good shape now though you can lower your TA to reduce the tendency of the pH to rise -- with the higher CH you now have, you can lower the TA with no problem (down to 80) using this procedure and can also make your pH target around 7.7. This should help reduce the pH rise and certainly the amount of acid you need to add. Adding the Borates will help even more.

Richard

[mas985]

What is your CH of your fill water? You mentioned that you refilled and your CH was 200 which indicates that is all from the fill water. That is fairly high and will build up over time. I have the same problem. When water evaporates it leaves the calcium behind and since the fill water has a fairly high CH, you are continually adding calcium.

[Ciscokid]

What is your CH of your fill water? You mentioned that you refilled and your CH was 200 which indicates that is all from the fill water. That is fairly high and will build up over time. I have the same problem. When water evaporates it leaves the calcium behind and since the fill water has a fairly high CH, you are continually adding calcium.

If this is true that would explain exactly what is going on with my CH.I will measure the CH of my Fill water tonight and double check. I am not to far from you. I live in Manteca, CA. So I would expect the fill water to be similar.

[chem geek]

To get from 200 CH with fill water to 550 CH after evaporation and fill, it would take 550/200-1 = 175% of your pool water volume to achieve that. That's an awful lot of evaporation, but perhaps is what is happening in your case. If you have a bucket of water next to your pool, you can see how quickly the water evaporates. Assuming a 4.5 foot average depth for your pool, you would need evaporation of 4.5 * 1.75 = 7.9 feet of evaporation per year or 0.26" per day (actually double that or around 0.5" per day since there isn't much evaporation in the colder months).

Richard

[mas985]

95" is less than what parts of Arizona and Texas experiences over the year so it really depends on where you live. Check out this Link for where you live to get an estimate.

I experience about 60" with is a full pool volume over the year so my CH almost doubles over the year.

EDIT: I should modify this some by saying that with a pool cover, you can greatly reduce the amount of water lost and thus the buildup of calcium.

[chem geek]

What a great link! I've bookmarked that one! Thanks.

[waterbear]

95" is less than what parts of Arizona and Texas experiences over the year so it really depends on where you live. Check out this Link for where you live to get an estimate.

WOW according to this my pool will lose it's full volume plus about 1 third more over a years time and my hot tub over 3 times it's volume!

[ndillon2]

Cisco,
Does your salt cell clog with scale build up? I have the same issues with CH and PH rising quickly. I go through 2-5 gallons of acid per week just to keep the PH down around 7.2-7.5. The SWG cell clogs with scale every day. I have to remove and clean with a power washer. MY Ch is also 600+ and there are scale flakes that come out of the return lines into the pool. I have considered bypasing the SWG as it is more problem than normal maitenance. However, I just feel like I am missing something and should not give up on it. Any help is appreciated. Thanks

[Ciscokid]

ndillion2,
I don't have a problem with scaling on the Cell.( other than the normal build up.) I clean it maybe once a month or so. Other than my CH being 550 all other chemicals are perfect. The pool itself is crystal clear.
Post all your chemical readings and maybe someone can better help with your problem.
Based on all the help I am going to raise my borates to see if it will slow my PH rise.Also I may airate the pool and get the TA down to 80. Thank you all for you information .