PH level consistently high

[lesandov]

Hello Everybody,

I am owner of a small swimming school in southern Mexico. As you might imagine my pool's bather load is heavy during the most of the season. I really had serious problems with very high CYA and low Ph levels last year, which derived in poor water quality, high expenses on chemicals, unscheduled pool shutdowns and patron's discomfort. This season I decided to use liquid chlorine at 13% as main sanitizer agent, after replacing the full 17,000 gallons of water for a fresh start. I had serious concerns about putting aside trichlor pucks, floculants, clarifiers, algae treatment and stuff alike; but right now I am more than happy with the results: my water is cleaner than ever.

My current levels are:

FC: 2.5
CC: 0.5 or less (once or twice a week I get a reading of .6 or little a bit higher; having non-existent CYA makes my pool prone to have unwanted higher levels)
Ph: 7.9
TA: 90
CYA:0 (I know this is far from your recommendations, but Mexican standards for facilities open to the public require this level for Indoor pools.)
CH: 100 (I've been trying to get calcium chloride to raise this, but it is not easy get that in a small town for an affordable price. I am still working on it)

Every sunday I pour 2 liters of Muriatic Acid to set the Ph level between 7.2 and 7.6; but during the week, it will consistently rise up until it gets to 7.9 by saturday. I am worried that this behavior may affect the temperature exchange device in the heat pump at some point. Do you think my hardware is in jeopardy?


Thanks in advance for you comments.

Luis
P.S. I am currently using FAS-DPD test kit (from TF guys) for FC & CC twice a day to have my levels well monitored.

 

[jblizzle]

Welcome to TFP!

Sounds like you are on top of things. If you are not allowed to have CYA, then you just have to live with that and just make sure the FC never drops to 0.

Your TA is a little high, so that will drive the pH up. As you keep the pH in check, the TA should drop and slow the pH rise. Keeping the pH in the 7s should not impact your equipment.

What is the pool made of? If it is not plaster, then there is no need to raise the CH. If you do need to raise it, do you have access to powder cal-hypo chlorine?

 

[bdrums]

Also, splashing from heavy bather load will cause a lot of out gassing which will cause pH to rise. You may not ever get to a stable pH while in heavy use.

- - - Updated - - -

Oh. And only adding acid once a week is not too bad. I have to add at least once per week.

 

[lesandov]

Thanks for your quick responses.

The Pool is made out of brick and cement, all surface covered with venetian tile. Considering this I assume CH level needs to be taken care of. Just a few of the tiny tiles had become loose and I am thinking that having such a low level might be the cause.

I'll check on the availability of Cal Hypo locally. Sometimes is not easy to get stuff like this in this side of the country. I even had to get my FAS-DPD kit in the US, get it accross the border and then shipped to me from there.

 

[jblizzle]

Yes, with the grout, you likely want to bump up the CH a bit. Remember that CH will tend to rise if you have a lot of evaporation (which Tucson does), but if you get a lot of rain (Tucson does not) that will lower the CH.

When I refilled my pool, I dealt with the lower CH for awhile by keeping the pH a little higher (upper 7s) because I did not want to add CH when I knew that all the evaporation would raise it. I have gone from about 130ppm up to about 500ppm in the last 3 years strictly from evaporation. I think next year (or the end of the season) it will be time for me to replace all the water to get the CH back down.