Green algae turned brown

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
Putting this post in for a friend:

He has a IG Vinyl pool, 18K, Sand Filter, 1hp pump

Here are the readings last night:
FC: 4
TC: 4
pH: 7k.2
TA: 100
CH: 250
CYA: 80

This morning:
FC: 4
TC: 4
pH: 7.4
TA: 100
CH 250
CYA: 80

Last week he went on vacation and when he got back he had green algae. When he got back he noticed the pump was clogged with leaves and cleaned the pump, and filter out. The water started moving again. Then he added 5 to 7 gal of bleach and 7 lbs of CYA because his CYA at the time was about 20ppm. He also added about 2 gals of algicide.

The problem now is it seems the algae is dead (overnight FC test) but the pool is brown. What can he try out to clear up the water?
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,047
SouthWest Alabama
Keep pumping. Run it 24 hours a day and backwash the filter as needed. It takes a while to clear even after it's all dead.

Why is he running his CYA so high? Does he have a SWCG?
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
Thanks Bama, I told him what you said. The reason why his CYA is so high is that the pool store told him to put that much in... I know, I know...
I told him to drain a little off to get it down to around 70ppm. He does have a SWG. I also said he does not have a bottom drain, so in my mind he has no way to efficiently get rid of dead algae below the skimmers. He said he has a pipe that he can hook up that will setup a bottom drain. I told him to try that out so he can increase the filtering efficiency.
 

dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
With CYA of 80, any clearing will be offset with another algae outbreak as his FC of 4ppm is too low. Unless he's running a swg, you should advise him to target 7-8ppm FC :goodjob:
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,047
SouthWest Alabama
What Dman said! Even if he's running the SWCG I'd recommend he keep the FC at 7-8ppm until the water is cleared up.

If he's getting good circulation from his return(s) he really doesn't need a main drain, but it certainly won't hurt anything to pump from the bottom.
 

Other Threads of Interest