Extremely High pH

Jul 29, 2011
28
Limerick, PA
Hi all,

I have a less than one year old plaster pool and battled high pH from the beginning - as expected with a plaster pool. Last year's start up with potable water was easy. We closed the pool in early December and just opened it last weekend and got the filter running. pH was off the charts. This is my first opening so to get things going, I brushed down the pool and through the pool cleaner in. The cleaner trapped about 2 pounds worth of calcium crystals – which makes some sense given the high pH. I started dumping muriactic (31.5%) acid in slowly, 1qt at a time. I’m now a gallon and a half in and pH is still too high and unmeasureable. Without being able to measure, I’m not really sure how long this could go on and looking for some rough advice based on a 20,000 gallon plaster pool? I would think I’d have to be close to getting it back in range but really have no frame of reference. Last year's start up from potable water only took two quarts to bring it in to 7.2.

Also, trying to get my CYA number in line as well. I have a SWG and targeting about 70. I have the TFT kit and if I use that test it shows I’m at 20. Two local pool stores are showing 40 and my neighbors kit shows 50. Test strips (yea, just for giggles) shows me within the highly accurate 30-50 range, which is convenience since that’s what the other three independent tests show. Nothing like accuracy! Since I don’t want to over add, which one do I believe? I ordered some new reagent just in case what I have is bad, but thought I’d ask.

Numbers.. my chlorine number are low as I just got the salt in but didn’t want to start shocking until I got the CYA up a bit and the pH down.

FC = 0
CC = have not measured yet
pH = ??, like a bazillion
TA = 100
CH = 250
CYA = 20

Lastly, is there a way to keep the pH down during the closed months? Thanks for any advice..
 
I would add acid one half gallon at a time, but otherwise just continue doing what you are doing now. There is a test, the acid demand test, that can determine this kind of thing for you, but you would have to have the special reagent and it hardly ever comes up, so not usually worth keeping the reagent around.

I'll bet your CYA really is 20. However, when in doubt add too little and fix it later. It is much better to end up a little low than to overshot and end up too high.
 
i was in a similar situation a few weeks ago upon opening my pool and it took 3 gallons of 20% MA added 1/2 gal at a time. I was surprised how much it took but I tested an hour after each addition until the pH was in range.
I'm really new here so make sure you listen to the pros. They will get you all situated.
 
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