pH keeps drifting up, again

[epearce]

This has been a very puzzling problem, and I think I have tried the typical "lower the TA" thing, and I still have the pH drifting up rapidly and need to add acid every few days. So, into the deep end. Two days ago, after lowering the pH to 7.2 and aerating it back up to 7.4, I was already back to a pH of 8 this morning! I've lowered the TA from 110 to about 80 after an aeration cycle. FC is maintained with about 1/2 10% bleach daily. The water is crystal clear. The numbers...

CYA 60
ph 7.4 - 8.0
TA 80 (was about 110)
CA 150
FC 3
chlorine demand about 3.5 per day, pool gets full sun all day.

Some more history... I did have a huge high CYA level (maybe as high as 600!), which has been worked down to 60 with incremental draining and refilling with softened well water over the course of the summer.

Any ideas?

 

[YippeeSkippy]

Wait, I'm confused- when you drop your pH and TA using MA....why are you then aerating the pH back up? Just leave the pH down at 7.2 and see where it goes on its own. You might try taking the TA down to 70 to see if tht helps?

Just my suggestion

Maddie

 

[JoyfulNoise]

Keep lowering your TA. If my TA is at 80ppm, my pH will rise very rapidly. I keep my TA down between 50-60ppm.

 

[mknauss]

And if CA means CH (calcium hardness) - watch your CSI as you are quite low in CH for a gunite pool.

Take care.

 

[JoyfulNoise]

And if CA means CH (calcium hardness) - watch your CSI as you are quite low in CH for a gunite pool.

Take care.

Thanks for catching that Marty!!

To the OP - you're adding too much softened water. Your calcium hardness is way too low. You should be at a minimum of 250ppm or else you will start etching the pool plaster. Please read through TFP recommended levels.

 

[epearce]

Thanks for catching that Marty!!

To the OP - you're adding too much softened water. Your calcium hardness is way too low. You should be at a minimum of 250ppm or else you will start etching the pool plaster. Please read through TFP recommended levels.

Indeed, "CH", its actually about 170, and I have been adjusted it back up to compensate for the dilution with the softened water.

I'll try bumping the TA down more. Back when we moved into this house a year ago, the TA was about 50, and the pH was low (< 7), but was easily adjusted up to 7.4 and was stable. This pH-rapidly-drifting-up thing is relatively new thing.