7.2 vs >8.2 Grrrrrrrrrrr

[Infidel]

I thought a low PH caused Algea. May be incorrect, but if this is true and your Taylor test kit is accurate, you would be hurting yourself. Again...I may very well be wrong on the ph/algea thing. You should wait for the experts to give you an answer.

Lack of Cl will allow algae to grow, high pH will lock up the Cl making it innefective, which is why I have 25ppm Cl with no affect. The Taylor kit doesn't appear to be accurate but I'm not sure what damage low pH would cause with regard to algae.

[mjs31]

Lack of Cl will allow algae to grow, high pH will lock up the Cl making it innefective, which is why I have 25ppm Cl with no affect. The Taylor kit doesn't appear to be accurate but I'm not sure what damage low pH would cause with regard to algae.

I can see your point on locking up CH levels, But low levels of PH will dissapate your chlorine requiring you to use more. Essentially this could lead to algea issues as well. Not sure which is accurate and which is not. I have the Taylor kit and it has helped me out greatly over the past few days. I do stress to wait for an accurate response from the experts in this forum. They can do wonders.

[duraleigh]

Anybody can write anything they want and post it on the net. Nevertheless, This excerpt was taken from an article about chlorine that seemed quite believable and well thought out. It should answer your questions about the relationship of Cl and pH

The amount of hypochlorous acid and hypochlorite ion that is produced when chlorine is added to the water is directly related to the pH of the water. At a pH of 6.0, 96% of the chlorine will become the desired "killing" form of chlorine, hypochlorous acid. At a pH of 7.0, 75% of the chlorine will become hypochlorous acid and at 8.0 the hypochlorous acid concentration is only 25%. At a pH of 7.5 (the average spa) the amount of hypochlorous acid produced is about 50%.

[waterbear]

Anybody can write anything they want and post it on the net. Nevertheless, This excerpt was taken from an article about chlorine that seemed quite believable and well thought out. It should answer your questions about the relationship of Cl and pH

Pretty much true. The ratio of any weak acid to it's corresponding ion (in this case hypochorous acid/hypochorite ions) is pretty much pH dependant!

[Poolsean]

"Lack of Cl will allow algae to grow, high pH will lock up the Cl making it innefective, which is why I have 25ppm Cl with no affect. The Taylor kit doesn't appear to be accurate but I'm not sure what damage low pH would cause with regard to algae."

With the high chlorine and no affect on the algae, you're probably dealing with high phosphates as well, which is just allowing the algae to feast in your pool. Check and treat for phosphates.

[waterbear]

Good point Sean, This might be one of the cases where phosphate removers are actually called for. Test your phosphate leves and also test your nitrate levels. If phosphates are high and nitrates are low then phosphate remover might work for you!

[Infidel]

Thanks for all the info. Here's some background:

Alk 120 (consistent with reading 2 wks ago)
Ca 350 (consistent with reading 2 wks ago)
CYA ~100+ from reading tonight, has been reading 72-80 last 2 wks
pH 7.6 OTO / <7 Taylor (as of 2am Texas time)

Cl is being read from the Taylor at 1:5, color is usually between the 3 and 5.
I'll grab a pH meter from work tomorrow and start checking the "real" pH and see what method is accurate. I use the K-2005 kit from Taylor.

Are you sure 6-8 ppm is suitable for lime green pool with CYA ~80? WIth regards to consistent concentration, I'm unable to distinguish between the 3 and 5 (15-25 ppm) on the color comparator, so if it's yoyoing, it's doing it between 15-25, which should be sufficient to keep things killed, even at the low point in the cycle, correct?

The pool is looking less green since adding acid 4-5 hrs ago. The low pH should be increasing the %hypochlorus according to Duraleigh's excerpt, which appears to be occurring. So, algae in spite of high Cl, may indicate pH is elevated and the active Cl isn't present in great enough quantities it sounds like.

Are phosphate / nitrate commonly performed by pool stores?