PH Rise after switching to bleach

[bigwillie]

Hi folks,

New member, but I've been reading on here for a few months. I have a fairly new gunite pool, opened in March, 2014. 22,000 gallons. Has an ozonator on it, for some reason. Ran with Ozone and low FC with trichlor pucks inline for a few months, until algae in June. Fought algae with powdered Chlorine until end of July, when I found this site. Noted that CYA was off the chart, so I did a partial drain and fill, and got CYA down to 100. Plan to go lower, but haven't done it yet. Anyway, Algae has been gone, and pool has been nice.

The problem now, is that I am having to add acid twice per week to keep PH in line. Of course, TA is now going down, and also CH has gone down. I put my current numbers below. I am concerned about adding this much acid. Only added once per month or so when using pucks. I know the pucks keep PH down, but just not sure why it continually goes up now? Is it still curing? Should I be concerned?

Any ideas would be appreciated. Thanks.


Current numbers (from Taylor kit)

FC 6.0
CC 0
PH 7.8
TA 80
CH 200
CYA 100

 

[jblizzle]

Welcome to TFP!!!

The trichlor tablets and if you were using dichlor powder are acidic and thus were counter acting the pH rise that could be due to the newer plaster and a higher TA. A rising pH is not uncommon when you get away from the acidic forms of chlorine (which also have the CYA problem), especially if your plaster is less than a year old.

There is no problem adding as much acid as you need to keep the pH in the 7s.

Please add your pool details to your signature as described HERE as it will help us help you.

 

[bigwillie]

Thanks. Is there anything in my numbers to suggest something could be done to slow the rise?

 

[JVTrain]

Two things were/are likely working against you. First, your TA was likely higher when you converted to bleach/liquid chlorine than it is now. Higher TA means faster pH increases due to aeration. As that TA number comes down, pH rise will slow. Whenever you add acid, the TA will go down. Second, the ozonator provides some extra aeration to your water as it passes through the unit. I would disable/disconnnect the ozonator entirely as it's really only adding extra aeration. If you have water features such as deck jets or waterfalls, use them less if you can and the pH will rise slow. They are large sources of aeration, which drives pH upward. Your current TA reading is "normal" range.

 

[Richard320]

pH will rise for the first year or so. It should be slowing down some with time, as well as the lowering TA. Twice a week isn't too bad for a pool that's only a few months old.

 

[bigwillie]

Thanks folks. I was wondering if the Ozonator would cause a PH rise, but I didn't see any discussion online. Seems like it should since it is bubbling. I'll turn it off and see if that helps anything. Not sure it is doing much anyway.

As to TA, the Pool Calculator says 70-90 range, so I guess I am getting close to the low end. Any thoughts on going lower than 70?

 

[jblizzle]

No problem going a little lower on the TA.

 

[RobbieH]

I don't own one, so I won't consider myself an expert, but it seems to me an ozonator would add aeration to the pool, which would cause a rise in pH.

 

[bigwillie]

I'll post PH results in a week or so after switching it off.

 

[bigwillie]

For those of you holding your breath waiting on results, I will say that PH is rising a bit more slowly now that I've turned off the ozonator. It appears to be only a small difference. I think I may try to measure and chart something comparing the difference, but the weather is changing here in Louisiana, so I think I'll wait until next summer.

If anyone else has any thoughts or experience, let me know.

Thanks.

 

[Smykowski]

My only thought goes back to Richard's post above. The new pool will have a substantial pH rise for a year. If next summer the rate is still as bad, then investigate further. Until then, do what you have to do, and just know that what you're experiencing is within the realm of normal.