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View Full Version : cya low, alk a little high, ph keeps rising



hkcon
07-29-2011, 11:33 PM
I am back with new questions...26,000 gals. gunite. I have not been able to afford the really good test kit yet so i have the dealer test for cya. I went today and everything was pretty good 5ppm fc, 7.7 ph, 20 cya, 130 alk, phosphates 300. So here are my questions
1. I have a 1/2 lb of cya dry and a gallon of liquid how much to get my cya up?
2. is 130 really high for alk?
3. is 300 high for phosphates?
4. my ph will not stay down at 7.5 or .6 it goes up every day.

Ty for the help i know is coming...you guys are the best...by the way the pool is perfectly clear but every now and then a little yellow can be seen and brushes away easily.

aylad
07-30-2011, 05:35 AM
I am at work and don't have my poolcalc handy, so I'll have to find your answer to #1 and edit this post with the answer. A TA of 130 is okay, but unless you're using trichlor to chlorinate, you'll find that lowering your TA to around 80 will help keep your pH more stable. About the phosphates, you can disregard that number. Phosphate removers are one of the latest gimmicks that pool stores use to separate you from your money. In a properly chlorinated pool, phosphates don't matter.

Odds are pretty good that the yellow you're seeing is pollen. Does t collect around the waterline?

Watermom
07-30-2011, 07:10 AM
I'll help you out with the CYA question since Jan didn't have access to her calculator. If you add 4 lbs. of the granular CYA, that will add 20ppm to bring you up to 40ppm total which would be a good level. (I do not know the dosing amounts for the liquid as I have not used it.)

waterbear
07-30-2011, 06:41 PM
2. is 130 really high for alk?
4. my ph will not stay down at 7.5 or .6 it goes up every day.

IF your pH is constantly rising then your Alk is too high (assuming you are using bleach, liquid chloirne, cal hypo or a SWCG and not trichlor, dichlor or MPS--non chlorne shock) Dropping the ALK down to 80 ppm or even a bit lower willl slow the pH rise from outgassing of CO2 which is the main cause of pH rise in a pool using unstabilized chlorine. However, if your poos is plaster and it is new then the pH will also be rising from the curing plaster. Also, if your pool is plaster you might have to adjust the calcium hardness to keep the water balanced if your drop the TA. Without more info I can't say more.


3. is 300 high for phosphates?

no, ignore phospahtes. Mine are over 3000 ppm and I have NO problems. They are just a money making scam for the pool stores. Before there were products they could sell you to remove phosphates no one ever tested for them. Nitrates are as big of a 'problem" (not) and they are not routinely tested because there is no product they can sell you to lower nitrates, you have to change water to dillute them.

hkcon
07-31-2011, 03:58 PM
ok ty guys, 26,000 gallon plaster pool 17 yrs old, cartridge filter (4 tall ones), 3/4 horse pump, solar, heater, spa (connected w/ spillover to pool), secondary pump for cleaner.
I use liquid chlorine (sodium hydrochlorite 10%), when I had zero cya the store wanted me to use 3 gallons of the liquid so I will put in the one gallon I have with the 1/2 lb of dry and see where I am. I will probably not try to lower the alkalinity unless I see that it is rising. I thought that you might say that about the phosphates, actually I was hoping...it is good to have you confirm that. I do not think it is pollen, I have nothing around the top, and it looks just like yellow algae, which I am very experienced at growing...LOL It has only happened twice and i brush it and it is gone, it happens on the afternoon sunny side of the pool.