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Thread: Green substance on bottom of pool

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    rrc1962's Avatar
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    Green substance on bottom of pool

    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...
    ----------------------------------
    24' Above Ground
    1.5HP Waterway Pump
    Hayward 120sq/ft Canister Filter
    Soon to be abandoned AquaSmart system in favor of the BBB system.

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    svenpup's Avatar
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    Re: Green substance on bottom of pool

    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.
    TFP Method Advanced Intermediate
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    Helpful Links: Pool School, BBB for Beginners, How to Shock (hint...it's a process not a product), Chlorine/CYA Chart, Jason's Pool Calculator

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    frustratedpoolmom's Avatar
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    Re: Green substance on bottom of pool

    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...
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    rrc1962's Avatar
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    Re: Green substance on bottom of pool

    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.
    ----------------------------------
    24' Above Ground
    1.5HP Waterway Pump
    Hayward 120sq/ft Canister Filter
    Soon to be abandoned AquaSmart system in favor of the BBB system.

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    duraleigh's Avatar
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    Re: Green substance on bottom of pool

    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.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    JasonLion's Avatar
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    Re: Green substance on bottom of pool

    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.

    Quote Originally Posted by rrc1962
    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.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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