green pool

[will23]

took cover off pool (24,000 gal) last week and pool has been green since then. Never had this problem before. was gone for about 1.5 wks with no pool care. have shocked and added 1.5 bottles of algicide 60(poly stuff). No change at all. Was directed to your website. and just added 12 gallons of bleach. Water analysis this AM was (prior to bleach)FC 4.74, TC 5.5, CC .8, TA 110, pH7.6, Ca310, CYA 37, copper and iron 0. Please help.

[PoolDoc]

Did you just open your pool for the first time this season?

Regardless, an effective anti-algae level of FC, for a pool with ~40 ppm CYA, is going to be 15 ppm or more. On your pool, that means using 8 gallon doses of 6% bleach till you get there.

Purchase a cheap OTO/phenol red test kit, and add bleach till you reach an orangish/yellow color (past dark yellow) level of chlorine. Hold the FC level the for a day or two, before deciding to raise it further.

[will23]

thanks, algae is all dead now. pool is very cloudy now and have tried flock without much success. Used both the type you sprinkle in skimmer and broadcast in pool allow to circulate and then turn off pump. Local pool dealer keeps telling me it is a filter problem. Just changed sand late last season. They also think it could be the valve on top of filter.
Thanks again

[aylad]

Are you sure the algae is all dead? Have you tried testing at night and again in the morning to make sure you're not still losing chlorine?

Keep in mind that chlorine kills the algae, but it is the filter that will remove it. If you see your pressure rising, then the filter is doing its job and just needs some time to work. Some of the other sand filter users, including the other 3 mods, add a handful of DE to their sand filters (just enough to raise the pressure by 1 psi) and that will help the filter catch smaller particles. However, if you don't see your pressure rising, or if you're seeing stuff blowing back into the pool, then you could have a filter issue.

I would get the smallest bag of DE you can find, add a cup or so through your skimmer, and then watch the returns to see if it blows back. If it does, then you have a filter problem to solve. If it doesn't, and you see your pressure rise within the next 30 minutes or so, then the filter is working and you just need to give it a good dose of POPP--pool owner patience and persistence!

Janet