The battle of rising pH

[azxd09]

First of all, I really want to thank everyone on this board for all your posts and advice. This is my first post, but I have been lurking for many months, learning about BBB. It has been great! I moved into a house with an existing 12K gallon pool. The pool was clear and sparkling, but the CYA levels were through the roof. I did a drain and refill, got my TF100 kit, and am now committed to the BBB method, although my wife now looks strangely at me when I get excited about the price of bleach at Wal-Mart . Thanks to everyone on the forum for all the great advice! I hope to be able to soon share advice on my experiences to help others in my same position.

I had a couple of questions. My TA was originally at 180, and with adding acid/aerating, I have now gotten it down to 100. I have noticed however that I am still having to add about 1/2 gallon of 29% MA every 10 days or so. I will add the MA, get my pH down to about 7.2, and without even aerating with my waterfall, 10 days later it is up to 7.8. Is this just something I need to deal with on a re-fill? I have used about 1 1/2 gallons of MA since the fill. One other detail (not sure how major or minor it is) is that when my pump turns on ever night (I have in floor cleaners), each pop up cleaning head pops up and lets out a few seconds of air bubbles before shooting out just water. I know this means a supply side air leak somewhere but I honestly don't have the time or money right now to get it figured out. Is this something that I can just live with, or could this be causing the rising pH by "aerating" every night for a few minutes at the beginning of every pump cycle. Also, if I plan on running the waterfall for 2-3 days each week, will this always be raising my pH, or does a lower TA cause aeration to have less of an effect on pH?

Thanks everyone for the help!

 

[Melt In The Sun]

It may not be a suction side leak...whenever the pump is off, any leak anywhere in the system will let all the water drain out of the above-ground pipes, filter, etc. Do you notice any drips when the system is running? Any little drip will slowly let air in when the pump is off. I wouldn't worry about it unless it causes problems, which it doesn't sound like it does. I have at least 3 tiny above-ground leaks, so I get this same thing too; when the pump kicks on the air purges and everything's fine.

As for the rising pH, that's not that bad! You're correct that lower TA means pH will rise less slowly. You're working it down right now, so just keep it up. If you haven't added borates to your pool, that would also help.

 

[Isaac-1]

You don't mention where your located some regions have more problems with pH drift than others based on dust that may get blown in, etc.

 

[azxd09]

Thanks for the info. I do not notice any external leaks while the system is running, but when the pump shuts off, some water escapes in a burst from the lid of the Hayward pump. Is this normal? The other issue with my system is that the backwash from the DE filter is plumbed through a separation tank and back to the pool. I guess it is for water conservation. Some people say this is common, others say it seems weird. I am wondering if this has the potential to let air in to the returns?

Isaac, thanks for the info, I am in the Phoenix area, so maybe a higher level of dust causes rising pH?

 

[jasonknox]

I had the same problem as you with rising PH. I kept adding a quart of MA every 10 to 14 days and it eventually stabilized at 70.

 

[Richard320]

On the pH: sounds like my pool. Massive acid consumption.

Part of that is keeping CSI negative, so I could dissolve scale from the walls.

But I noticed after a partial refill with lots of rainwater, my TA dropped to 50+/- And the pH is flatline. Now it's like 6 oz MA/week. And I'm still watching the scale fade!

It seems that every pool has its own personality. Some like high TA, mine seems to like low. You could try aggressively reducing TA by loads of acid -pH to7.0 - then run everything you can to aerate it. TA will go down, it just takes a lot of acid to do it. Eventually you'll reach a point where it stabilizes. And then you can coast.

 

[Prav]

Mine kept creeping up until (a) TA got down to about 60 and (b) got 50 ppm borates. Now, rather than adding 10-12 oz MA/wk, I now so that every 15-20 days or so.

 

[anonapersona]

I have the same problem. It is worse when we have no rain, as rain has no TA but tap water has 340 TA. So a regular topping off of the pool where I add an inch or two means that TA goes up by maybe 10 or 20 each time. That means that my pH is constantly rising until I drive TA down pretty low, like 60 or 70. That is bordering on unstable I fear, so I just resign myself to always adding 2 cups of MA, or maybe more, with every chlorine addition.