Alkalinity Problem with low PH water

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.

Alkalinity Problem with low PH water

Postby cj » Sun 26 Feb, 2006 15:40

My "raw" water has a PH of about 5 and alkalinity of 10ppm. With the Taylor testing kit the water has a base demand of 22 drops. The problem I'm having is by the time I add enough soda ash to correct PH my alkalinity is around 250ppm - way high. Attempts at lowering the alkalinity results in low PH and the need for additional soda ash and resulting higher alkalinity levels. Any suggestions on how to get out of this loop??

Pool Help

Total alkalinity & pH problem

Postby Pool Help » Sun 26 Feb, 2006 18:31

I would aim to get the pH within the recommended range. You say this pushes your total alk way up. What happens when you ignore the total alk?

Usually high total alk pushes the pH up, but your fill water will keep bringing down both the pH and the total alk. I would guess that if the pH were fine, then the alkalinity level would kind of stabilize. If it remains high, try to keep the hardness level nearer the lower limit (200ppm), to offset the scaling effect of high alkalinity.

Adding soda ash followed by acid is really giving the pool a beating, causing you headaches and burning up unnecessary $$s. Ignore the total alk for a while and post back the results here.

PH and total alkalinity

Postby cj » Mon 10 Apr, 2006 13:19

So far so good with just maintaining proper PH and avoiding alkalinity adjustments. Water is clear and no particle precipitation.
I'm maintaining an indoor, covered "Endless Pool" and using their recommended bleach sanitizing system. Which works very well. With the addition of the sodium hypochlorite (bleach) it causes the PH to slowly rize. I've been bringing the PH down with dry acid added by "pooling" in the middle of the pool and it has lowered the alkalinity from 250 to 175.
Pool Help

PH and total alkalinity

Postby Pool Help » Mon 10 Apr, 2006 15:20

Sounds like things are finally stable. Great to hear it.

Your additions of dry acid in the way you described will keep bringing the total alkalinity down slowly until it comes within "normal" range.

Using the sodium hypo is a really good way to offset the low pH of your fill water, and is very economical too. Only thing you might need to watch is the TDS, which has been known to rise with constant use of the sodium hypo (depending on the specific product).

Also watch the hardness level to prevent scaling.

I'm sure your pool is more balanced and the water less harsh now, and probably needs less maintenance.

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