Dark Green Pool, but no algae.

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
Jim in Irving Texas

Dark Green Pool, but no algae.

Postby Jim in Irving Texas » Sun 16 May, 2010 16:57

I have a 15,000 gallon above ground vinyl pool with submersible steps and a sand filtration system. I run the pool year round, but it is of little trouble in the winter. I use standard chlorine. Three weeks ago I started getting the pool ready for use. There was a small amount of algae on the sidewalls, bottom and steps (the steps are always hard to stop algae growth on due to circulation) so I backwashed the pool, then swept it and the water turned light green. I added a little algae control, adjusted PH and ALK then shocked it and went about my business. The pool turned Dark green.Two days later I took a sample in the pool store and explained all of the above. They told me the FC was a little low along with the PH. They instructed me to again put Algae control in the pool adjust PH and shock it again....As per there request I have repeated this procedure once again. Now my pool is the darkest green you have ever seen and the chemical levels are all perfect. I forgot to mention I was instructed (between doses) to add clarifier to (remove the suspended green paricles) from the water and clear it up....Today I went back to the pool store and the results were as follows:

FC 3.0
PH 7.4
ALk 80
Hardness 200
CYA 90
Phosphates 0

I purchased (at their request) a bottle of "pool first aid" a super clarifier I belive and per instructions used about half the bottle or 16 ounces. I think it"s greener than is was this morning, but not sure.

I have noticed through this process the pool store has not checked copper levels in the water, however there is a space on their form for it. Sounds like I have a copper problem. What do I do now?

chem geek
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Dark Green Pool, but no algae.

Postby chem geek » Mon 17 May, 2010 00:01

It does sound like the algaecide you used had copper in it and that the subsequent shocking raised the pH that then colored the water green, though now your FC and pH are down. Your CYA level is high which means it will take a higher FC to get rid of algae, but assuming that the green is solely from copper you can 1) lower the pH and see if it lightens up and 2) use a metal sequestrant.

Depending on how much copper you added, you could have a difficult problem to clear up, but the sequestrant and clarifier are ways to get there. I just hope you don't get significant staining -- at least with a vinyl pool that's less likely -- if you had a plaster pool, well, it could be a lot worse.

In the future to control algae I suggest you read the Pool School to learn how to properly maintain your pool and the FC/CYA ratio to maintain.

Dark Green Pool, but no algae.

Postby todd » Thu 20 May, 2010 19:35

I have the exact same problem. My pool is only 5400 gallons and Leslie's pool told me to do the same thing as you. Chemical readings are fine and they tell me to just keep adding the First Aid. That was 4 days ago and there is no improvement. He checked for metals in the water and found none. Have you had any success since your post?

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