Algae Problem

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
cajunslo
Pool Newbie
Pool Newbie
Posts: 9
Joined: Wed 22 Jul, 2009 13:06
My Pool: Above Ground, 6' , 18' round. 325# inground type sand filter and pump.
Location: Louisiana

Algae Problem

Postby cajunslo » Sat 25 Jul, 2009 04:54

I do have a good test kit, just ran out of some of the liquid drops. Will have to order some.
Since i cannot be at home for a few more days, I let my wife go ahead and add the CB 7 and clarifier. So
she can stop doubting me about the information i am getting from you guys. I am not sure at this time what
brand chemicals our home town pool store sells, so could you give me a few name brand metal sequestrant with the HEDP. Also I dont have any heat exchanger or heater. Do you believe i am dealing with a metal
problem rather than a algae problem, given the fact that two days of shocking and vaccuming did not make any change to the water. It still remained green with no clarity. Also we have been catching rain showers
just about every afternoon for the past few days and a few days leading up to the green monster. We have
had our pool for about 8 years and have not had any problems before with our water rural water system.


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Algae Problem

Postby chem geek » Sat 25 Jul, 2009 13:38

You could have both a metals problem AND an algae problem, but your bucket tests seemed to confirm the former more than the latter. Usually the metals won't cloud the pool so that part could be algae starting to grow (and clearing cloudy water with chlorine take time, even in a bucket test) though with copper in the pool that should be inhibiting algae growth. If your CYA is really 50 ppm then if you've got algae you'll need to shock the pool with an FC level of 20 ppm, but that would raise the pH making the green copper problem worse. So I'd just maintain an FC in the 5-10 range for now, deal with your metals problem, and then you can clear the algae by shocking later (lowering the pH first before you shock so you could just raise the pH to 7.2 after clearing the pool of metals and then shock with chlorine to 20 ppm FC and hold it there until the cloudiness clears -- see Defeating Algae ).

See this post from waterbear for brands of HEDP metal sequestrant.
cajunslo
Pool Newbie
Pool Newbie
Posts: 9
Joined: Wed 22 Jul, 2009 13:06
My Pool: Above Ground, 6' , 18' round. 325# inground type sand filter and pump.
Location: Louisiana

Algae Problem

Postby cajunslo » Mon 27 Jul, 2009 13:18

Ordered a new test kit this morning.
Today's Pool Store Readings.

Saturation Index -0.20
Total Dis. Solids 0
Free Chlorine 16.0
Total Chlorine 17.0
Combined Cl 1.0
PH 7.4
Cyanuric Acid 78
Cooper & Iron 0
Total AlK 100
Adjm Alk 74
CH 150

The Green has disappeared and now the water is basically clear until the bottom last 4-5 ".
We Brushed but did not backwash, ( 2 different pool stores told my wife this ). Since it has been cloudy
going on the 3rd day, i told my wife to backwash tonight.

We did not treat for metals, so i guess since it started to clear up that wasn't the problem.
Also had to take a couple of sections of hose from the crawler, noticed that the hose has some green
build up. We will soak the hose in a bath of chlorine to clean it out. I am wondering if we were just
circulating algae around.

Please advise with any suggestions.

P.S. To all the contributors to this forum. You guys are doing a great service to all of us that can't afford
to hire a pool guy.

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