Green substance on bottom of pool

rrc1962

Member
Jun 6, 2010
23
Nashville, TN
This my first issue ever with the pool. I guess I've been lucky.:) I've got this green substance that appears overnight on the pool bottom. The water looks clear, but after I vacuum it gets a little cloudy. I'm thinking we had an outbreak of algae due to the very warm weather. I don't have a good test kit, but I know my FC is between 9 and 10, and TA and PH are a little low, which I'm dealing with now, and CYA is between 40 and 50. I raised the FC a bit yesterday to try and kill off any algae. It was around 6 yesterday. What's my best strategy here? Should I shock or go get some algaecide from the pool store?

I have not switched to BBB yet just because I'm using up existing bac-paks. Could this green stuff be metals in the water from the Aquasmart?

Also...Once I switch to BBB, can I still use pool store shock. I have about a 2 years supply that I bought cheap from a neighbor last winter.

Thanks...
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
Algaecide is better at preventing algae that eradicating it once you have it.

Borax can be used to quickly bring up pH.

Baking Soda can be used to quickly bring up TA.

Bringing FC up "a bit" wont do it. At CYA=50 your shock FC level is 20. This is not a one time thing, as algae quickly consumes FC. You need to keep bringing the level up, as often as once per hour, to overcome the algae ("how to shock" link in my signature). Have you read pool school?

What is in the "shock" you want to use? If it is dichlor or trichlor it will raise CYA. If it is cal-hypo it will raise CH. It is true that low CH isn't damaging to vinyl pools, high CH is bad for all pools.
 

frustratedpoolmom

TFP Expert
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In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
To determine if this is algae, you should do an overnight FC loss test. If you lose more than 1ppm, you should shock the pool. Be sure to check areas of poor circulation (wedding cake steps, ladders, etc.) for algae that can be lurking out there...
 

rrc1962

Member
Jun 6, 2010
23
Nashville, TN
It does seem to lurk around the steps. I figured that the algae would have a hard time with FC up around 9 or 10. I think I'll shock tonight. The shock I have is called Blast from a company called Swimway.
 

duraleigh

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Apr 1, 2007
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Sebring, Florida
rr,

BBB is best described as careful testing and then knowing what to do with the results. It's also very important to know what you are putting in your pool and what the results will be.

You are saving yourself a few dollars by throwing that stuff in the pool but you will quickly spend much more than you are saving as you try to work yourself out of what appears to be an algae bloom...(although your numbers wouldn't indicate that)

If you do not have a test kit, how do you know the test results for your pool? How old are they? How are you dealing with TA and pH being a little low? How low are they?

It's probably pretty easy to get your pool fixed up and in good balance but you will have to give the forum some more accurate information to work with.
 

JasonLion

TFP Expert
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LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Is the only reason you think you have algae that the water gets a little cloudy after you vacuum? That is normal and nothing to worry about. If there is some other reason you think you have algae, then fine, but I didn't see it in your post.

rrc1962 said:
but I know my FC is between 9 and 10
How? I'm with duraleigh on this one, unless there is something you aren't telling us, there isn't any way you could know what your FC level was that closely so you just guessing. Guessing work just fine until you guess wrong, then it can get rather expensive.
 

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