Refill and balance

[m73013]

I am new to this site. I live in Mesa, Az, 30 miles east of Phoenix. My pool is a 1 year old, plaster, 8500gal, Hayward cartridge filter w/1 hp pump with selectable on/off sprayer-aerator and 2 foot wide direct-dump water spill. I have only recently taken an interest in caring for the pool, this is all new info to me. The CYA and CH levels (100+ and 1200+ respectively, were out of control). I did a COMPLETE drain and refill on 3/2/10, the fill water readings were as follows: FC-1.0 CC-1.0 TC-2.0 pH-7.4 TA-140 CH-410 CYA-0.00 Temp-67'F. After adding muriatic acid, 10% liquid chlorine and 1 gal liquid CYA, the levels as of 11:00AM 3/10/10 are: FC-3.0 CC-0 TC-3.0 pH-7.7 TA-105 CH-420 CYA-34 Temp-65'F. The pool, currently, is sparkling clear.
I have two concerns: 1) my pH seems to continually rise, for which I add muriatic acid and have become very judicial as to how much I run the aerators and, 2) at what levels should I keep the pool when it becomes +/- 110'F and extemely sunny this summer?

 

[frustratedpoolmom]

Hi and Welcome!
What are you using to test with? It is odd that the PH would rise after adding acid to lower the TA that much....

Refer to the Pool School article on "Recommended Levels" - you want your TA on the low end if rising PH is a problem (as in your situation). So every time the PH drifts up, just add enough acid to lower it to 7.2, this will eventually lower the TA into range too. There is an article about "How to Lower TA" as well, but that is only if you want to speed the process up, that's entirely up to you.

You probably will want your CYA between 50-60. If you have an inline chlorinator, you can use tablets for now to build the CYA levels, the acidity of the tablets will help keep the PH from drifting up. As your CYA level builds, you need to keep your FC level in accordance with the CYA/Chlorine Chart (see my sig).

It is normal for PH to continually drift up while new plaster is curing, it will do this for the first year or so. When you have aeration, it becomes more pronounced. So hopefully this year you will see more stable levels - especially if you keep your TA at about 70.

Hope this helps, if not ask away!

 

[m73013]

Thank you frustratedpoolmom for the quick reply. I use the TF-100 test kit. I do not have an inline chlorinator; I do, however, have a puck floater and trichlor pucks (which is how the CYA ran out of control during the first year). I will use that set up to raise my CYA levels. As far as the pH, can I infer from your info that if I add sufficient muriatic acid to lower the TA to around 70, that having that lower TA will then aid in keeping the pH in check?

 

[Richard320]

Your pool doesn't look too far out of whack. How long has it been circulating since you added chemicals? I find I get impatient. If I add something, I won't test it again for 24 hours, and the pool calculator has always hit it on the nose.

Play with the pool calculator some. Plug in a new temperature then fiddle pH and so on until you get the right CSI. Then you'll have an idea for the hot weather.

 

[frustratedpoolmom]

Thank you frustratedpoolmom for the quick reply. I use the TF-100 test kit. I do not have an inline chlorinator; I do, however, have a puck floater and trichlor pucks (which is how the CYA ran out of control during the first year). I will use that set up to raise my CYA levels. As far as the pH, can I infer from your info that if I add sufficient muriatic acid to lower the TA to around 70, that having that lower TA will then aid in keeping the pH in check?

You never want to target TA when determining how much acid to add. You always want to target PH. If you were to add all that acid at one time to lower the TA to 70 then the PH would then be too low. Refer to the "How to Lower TA" article for more information if you want to speed up the process for lowering TA. Since you already have an aerator, it would be fairly straightforward for you to do.

So every time the PH drifts up above 7.8, simply target 7.2 for dosing purposes, and eventually the TA will drop into range - and yes, maintaining the TA at around 70 will help keep the PH in check.

I wouldn't worry about things like CSI for now - become more comfortable with the ABCs of pool water chemistry and if you want to worry about CSI in the future you can always research it. Provided you maintain your levels in the ranges referred to in the "recommended levels" article, your CSI should be ok and not something to be overly concerned with.

 

[m73013]

Hi Richard, good point, I too get impatient for things to transpire. My last chemical add was yesterday morning, 4 oz of muriatic acid, the goal was to lower the TA from 105 to 100. Had no affect though. I just read the next response from frustratedpoolmom while typing this, my approach (targeting the TA) was incorrect, therefore, my zero net-change in TA. I will lower my pH to 7.2 with acid, then rebuild it with more aeration, my goal will be a TA of 70.

 

[polyvue]

Hi Richard, good point, I too get impatient for things to transpire. My last chemical add was yesterday morning, 4 oz of muriatic acid, the goal was to lower the TA from 105 to 100. Had no affect though. I just read the next response from frustratedpoolmom while typing this, my approach (targeting the TA) was incorrect, therefore, my zero net-change in TA. I will lower my pH to 7.2 with acid, then rebuild it with more aeration, my goal will be a TA of 70.

Yeah, it takes time for the TA to go down... perhaps several months. But since a TA of 105 ppm is not greatly out of bounds, I would suggest the gradual approach.

And pull those pucks out of the water BEFORE you reach your CYA goal! It takes a while to dissolve and you don't want to overshoot the mark.