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Thread: Added too much algaecide...what to do

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    Added too much algaecide...what to do

    I am a new pool owner it was just installed last fall, I have been watching this amazing resource for sometime now I have a question of my own. We also just brought home our second child, and that is what I am blaming this brain fart on!!! I was given HTH Algae stop 15( as well as other HTH chemicals as a sort of pool opening gift from the inlaws), So my pool has been running amazingly thanks to helpful tips from this website, I also drove down to a Leslies store in Buffalo and bought a FAS-DPD test kit, on this sites recommendation. It has been great the water test right in range all the time but lately I had been getting a slippery feeling on the bottom and sides of the pool, no visible algae but I though well i have the chemicals right here I might as well add some algaecide. The direction on the box recommend an initial dose of 135 ml per 10,000ltr of water ( my pool having approx. 84,000ltrs) or a maintenance dose of 80ml per 10,000ltrs. I though I would add the lower amount as there was nothing visible. This is where the brain fart comes in, I in a moment of exhaustion though that there were 100ml in a litre, so I figures i needed about 8.4 ltrs of the stuff which was handy because I had a 8 ltr jug. So in the entire jug goes. no real issues. until about 12 later I decided to also shock the pool, as soon as the shock hit the water , it turned to milk. I panicked ran to this website realized my mistake and am not really sure what to do.... since then the pump has been running full speed fro two days the water is clear, there was a ton of dead algae on the bottom that I vacuumed to waste( looked like sand), and I also backwashed the filter for an extended time, but now I am trying to add water and it is foaming up quite a bit. Any suggestions? Would it be safe to swim in? I have tested the water and these are the results

    FC= 3
    CC= 0
    Salt 3100
    Ph 7.5
    CYA= 40

    The Products used:

    Algae stop 15 by HTH (arch chemicals)
    N-alkyl(40%c12 50%c14 10%c16)Dimethyl Benzyl Ammonium Chloride .......15% 8 litres

    Shock Treatment by HTH
    (it has no chemical composition on it, don't even see it on website I think it is from Costco) 454gram bags and I used 2.8 bags as per directions of 150 grams per 10,000ltrs of water.

    any assistance will be greatly appreciated....


    Ontario Canada

    16* 32 Humpback kidney with 3 foot shallow end and a 8 ft deep end so approx 20K gallon
    Hayward Ecostar variable speed pump, 1.5 inch plumbing, hayward 24" sand filter with zeobrite media. Raypack 266K Btu digital heater. Hayward Aqua Rite Salt Generator. Aquagenie skimmer/return combo. LED Lights.

    Fairly full sun

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    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: Added too much algaecide...what to do

    Welcome to TFP!!!

    If you are seeing algae in the pool, you need to follow the SLAM process. [slam:r9d4cjsq][/slam:r9d4cjsq]

    Chlroine will also take care of any problems the algeacide is causing. {And I hope you are aware that there is rarely ever a need for that stuff}
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    TFP Guide

    chiefwej's Avatar
    Join Date
    Jun 2011

    Re: Added too much algaecide...what to do

    If you are using powdered "Shock Treatment", you are not using the methods and chemicals recommended here. You are adding a lot of unneeded chemicals to the pool. If you follow methods in Pool School (button upper right on this page) you won't need algaecide or other additives. Chlorinate with liquid (bleach) and control pH with muratic acid to lower or borax to raise covers 99% of what we do.
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    techguy's Avatar
    Join Date
    Jul 2010
    Antelope, CA

    Re: Added too much algaecide...what to do

    A couple things... algaecide is for the Prevention, not the removal of algae. Chlorine is the chemical to kill algae and the best form is liquid chlorine (bleach). Solid forms of bleach/shock/sanitizer can be slower acting, typically add too much CYA (conditioner), and effect other water balance levels.

    Also, algae will grow in clear water and make your pool feel slimy anytime the FC (free Chlorine) level is too low for your CYA level. Since you are using solid forms of chlorine (bags/pucks/tabs) you are likely adding CYA. So, if your CYA is 40, your FC MUST stay above 3 PPM or you will grow algae and you will get slimy. Sounds like a SLAM would be your best course of action.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

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