I have to bring down my PH to adjust TA...

[talbrecht]

I have a SWG quartz pool, 11,000 gals. Our equipment is Pentair Intelli Chlor and Pentair Intelli Flo.
We just reduced water volume by 8% to bring the CH down to 350. After re-filling the pool our specs are>

PH: 7.8
CL: 3
FCL: 4.0
CYA:50
SAlt: 3500
TA: 120
Borate:70
Water Temp: 72

I need to bring our TA down so need to add 55 of acid according to the pool calculator (also need to add some CYA).
The guy at the pool store says we can only add 16oz of acid per day.

I this true? If not what is the most we can add at one time?
Thanks,
Terry

 

[257WbyMag]

Typically, you can add what is called for slowly, but all at once. This is of course unless you have new plaster and the plaster is under warranty. When you plaster is under warranty, you have to play by their rules.

Very large amounts of acid, much larger than 16 oz., can be added to your pool safely, provided that you are doing it correctly. This involves only adding it when the pump is circulating water (true of all chemicals) and by pouring it slowly in front of a return jet. Be sure that the pump continues to circulate the water for at least an hour after additions.

 

[PaulR]

The amount that is safe to add will vary depending on starting pH, TA, and borates. Basically you want to avoid lowering pH too far.

According to the Pool Calculator, starting from pH 7.8, TA 120, and borates 70, it looks like 55oz acid will bring TA down by about 20 and lower pH from 7.8 to about 7.3.

Which of course you add slowly in front of a return jet with the pump on, as Mag said.
--paulr

 

[frustratedpoolmom]

CL: 3
FCL: 4.0

FC + CC = TC

Your CL can't be 3 if your FC is 4...something isn't right?

Is your CL meant to be CC? or something else....?

 

[talbrecht]

Thanks frustrated pool mom. I'll have to talk to my husband when he gets home. We're still sort of new at this. He takes the samples and does the readings and I look at results let him know what needs to be added. He wrote: CL:3 and FCL:4 I would assume that CL is supposed to be CC. Why can't that be? Now that I look again at what they mean I'm not sure why the CC would be 3. We only use the attached spa about 2x per week on the weekends so you would think the CC would be closer to 0 - right? I don't see any reference in POOL SCHOOL as to what the TC reading should be. Looks like optimum it should be equal to FC - right?

 

[frustratedpoolmom]

Right - you don't want CC.