PH going up again!

[Mr.Mooks]

Hello all. First off I do have and compu pool SWCG on my AG 15x25 52" pool. I had been on here before mentining about my high PH and Alk levels. I used the muratic acid and it came down to the proper level. But it going up again. I have read that some people have this issue with SWCG's! Is it ok to add muratic again to bring it down? It has only been 3 weeks since last edition. My big fear it that my 4 year old daughter has very sensitive skin which was why we choose a SWCG pool to keep levels constant. Will the muratic start to build up and cause skin damage? Does it disipate? Any help would be great.

[aylad]

It is common to have a pH rise when using a SWCG, because of the way it works. If you can drop your TA to around 80 ppm, and drop the pH to 7.6, it will be the most stable, according to the SWCG gurus around this forum ( I don't have a SWCG, but am debating adding one to my pool). It is common to have to add the acid to keep the pH down.You don't have to worry about skin damage due to the acid use, as long as you keep pH above 7.0, and as long as you allow the acid to completely disperse before swimming in it. I have actually accidentally splashed some directly on my hand while adding it to the pool, and just rinsed it off in the pool with no further effects. (Not that we advocate that--you should always take utmost care while handling muriatic acid, because it is nasty stuff--but sometimes accidents happen)

[waterbear]

Post a full set of test results and we can better help you. Also, post the make and model of the SWCG and (very important) the test results need to include CYA and TA levels, pump run time, and FC level.

[Mr.Mooks]

Thanks for your help. I am going to check all the information about my pool and SWCG make and models and put in my signature this weekend. As for the levels I do not have a Taylor yet so I am relying on the pool store. I know this is not good though its the best I can do for now. I know the CYA level is low beacuse I did not realize I still had to use it with a SWCG and my CL levels have been dropping and I am going to burn up my plates. Added some liquid CYA yesterday and have a water sample to take in today. When it is done I will post results.

[Mr.Mooks]

Ok. Just got back from the pool store and here are the results.
FC 0.2 ppm, TC 0.3 ppm, CC 0.1 ppm, PH 7.9, Hardness 260 ppm, Alk 167 ppm, CA 10 ppm, Phos 100ppm, Salt 3400ppm.
Pump runtime is 12-14 hrs per day in the daytime off at night.
As I had mentioned I just started to the liquid CYA yesterday afternoon and I only used 1/2 a 1 gallon bottle as I did not want to go to high. So I will add the rest later and also somemore Muratic Acid. Pool is totaly clear even with these numbers. Pool is 36000 liters.

[aylad]

Yes, your CYA is low, and does need to be raised, which you are working on.....and I'm willing to bet that Waterbear's going to tell you to drop the alk to around 80 ppm or so and see if that doesn't help slow the pH rise...

Janet

[Mr.Mooks]

Hello. I have added the Muratic Acid, the last 1/2 of my 1 Gallon liquid CYA and some more salt. Waiting for a few hours of circulation and then I will retest. Also I did this post because I have put all my info about my pool in my signature. Thanks again for everyones help. Carl.

[CarlD]

Yes, I absolutely agree that TA needs to be lower. I've found that if your pH trends up, a lower TA is better. If it trends down, a higher TA is better. If it doesn't move, don't mess with it!

Carl

[waterbear]

Yes, your CYA is low, and does need to be raised, which you are working on.....and I'm willing to bet that Waterbear's going to tell you to drop the alk to around 80 ppm or so and see if that doesn't help slow the pH rise...

Janet

I was going to say 70!

More important, with a CompuPool unit you want the CYA at 100 ppm, particularly if you have one of the non reversing ones. This will minimize the cell on time (and the speed at which the cell scales) while maintaining the FC (keep it at 5 ppm or a bit higher with this CYA level). Minimizing the cell on time will mean less generation of hydrogen gas in the cell which means less aeration of the water which means less outgassing of CO2 which means slower pH rise. (Outgassing of CO2 is the main cause of pH rise in salt pools, assuming no new curing plaster.)

Lowering the TA to 70 ppm will also slow pH rise from outgassing.

[Mr.Mooks]

Thanks Waterbear. My compupool SWCG does switch polarities. Now that I have added the stuff I have I will get the water tested again. A least with waht I have added I am heading in the right direction. I will post the results of my next water test.