New Home! First time pool owner in the NE (RI)

[PoolDoc]

Copper can definitely cause a greenish tint, but so can iron under certain conditions.

What sort of pool surface do you have (vinyl, plaster, etc) and what kind of filter?

[Bassist286]

I have a Plaster / concrete pool bottom with somekind of fiberglass-like wall about 3-4 feet tall. My pump and filter are Hayward PPR s244T high rate sand filter with a Hayward 75 gal/min pump.

Going to do the overnight chlorine test tonight to be sure the water is "clear". Hoping it's not Iron or copper contamination.

[PoolDoc]

What is the pH level?

Low pH can keep copper in solution, in spite of high copper levels. But, I've occasionally seen low pH with high alkalinity occur as a possible cause of greenish clear water.

Also, it would be good to test your sand filter. If you really have a 75 gpm pump, you may have blown a lot of your filter's sand out, during backwashes. One way to check is add a quart or so of DE powder to the skimmer with the pump running. If it blows back into the pool, via the returns . . . your filter needs service, and your pump may need downsizing. If it STAYS in the filter, it will help remove algae particles, and may help remove copper or iron, but will cause the filter to stop up more quickly.

[Bassist286]

I'll run a full test suite tonight and report the numbers. I haven't tested my TA and pH in about 5 days. 75 gmp does sound wrong - I'll double check.

[Bassist286]

Just tested everything again. We had a ton of rain over the past week so I expected the water balance to be off. Also did the overnight chlorine test. It passed (9.5 ppm FC last night, 9.5 in the am and 0.5 cc). Water is still a slightly greenish tint but clear.

FC-9.5 ppm
CC - 0.5 ppm
pH - 7.0 (added 4lbs of Borax just now)
TA - 110
CH - 150 (rain must have lowered this. ) Gonna add Calcium if pH is over 7.6 or higher when I get back from work.

Any other ideas on the slight green tint? Haven't testing the filter yet with DE. Pump says noting about GPM, no idea where I got that number.

[PoolDoc]

I would suggest waiting a week or two, before worrying about the color. For reasons I don't fully understand, pools can open green and clear, but then turn blue after a week or so. Iron can do that, but I haven't always seen the characteristic rust colored backwash that would be expected.

Do NOT add calcium when the pH is higher; it is MUCH better to do so when it's low. However, I should ask, why do you need to add calcium? It's ONLY needed on inground concrete pools -- is that what you have? Even then, once your pH goes up, your TA will rise as well. With values of pH=7.6; TA=120; CH=150, your water is plenty close enough to 'perfectly balanced'.

BUT, if you do add calcium, never add a complete dose at one time. Multiple small doses are much, much less likely to result in your pool looking like milk!

[Bassist286]

The Pool calculator shows CH minimum to be 2501 Is that wrong? If i'm at 150- it would seem , according to the calculator, that I have a good amount to go. I think I might have missed something.

[Watermom]

By any chance, is the 2501 in your post above supposed to have been 250! instead?