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Thread: CYA Levels, Shocking, Yellow/Mustard Algae

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    Join Date
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    Re: High CYA Levels, Shocking, Yellow/Mustard Algae

    Hi,
    Longtime lurker. I have the dreaded Mustard Algae. It all started when I didn't know my power board had blown the capacitors on my Auto-Pilot. Replaced Auto-Pilot and Salt Cell, generating good chlorine now, but I have the dreaded mustard algae. CYA of 60, so I'm prepared to raise pool chlorine to 40% of CYA tonight, do 64oz of Polyquat-60 tomorrow morning, raise pool to 40% of CYA tomorrow afternoon, then vacuum, thoroughly rinse out the cartridge filter and pray to the pool gods that I can be algae free. Is this still the preferred method? It's funny, when I bring chlorine to 15 or so, algae disappears, but with it at the normal 3-5, it seems to grow over the next day in my shaded areas under the waterfall. BTW, have a borate pool and took borates from 30 to 50 (didn't realize guidance had changed) and it didn't deter algae growth even with TC and FC above 5.

    Also, have a stone waterfall, so It looks like I need to let that run for several hours after I shock tonight. Should I be doing 60% of CYA or 40%? For me it is the difference of 7 gallons or 10 gallons of 8.25% bleach. Also, without any pump out and SWG not working earlier in the year, algae had conumed 25ppm of my CYA - anybody ever heard of that? CYA wnet from 60-35.

    All - I had hijacked a 6 year old thread, but this was thinking from chem geek
    1st chem geek post
    Re: High CYA Levels, Shocking, Yellow/Mustard Algae
    I'd be interested in what happens with the PolyQuat. If its instructions for use for existing algae are to first shock with chlorine, then add PolyQuat algaecide, then shock again (perhaps over a period of days), then this might be a reasonable alternative for killing yellow/mustard algae in high CYA pools where one wants to keep the higher CYA level. Though your longer-lasting PolyQuat is one maintenance approach, 50 ppm borates could be another. Let us know the specific instructions for the procedure that you use.

    I presume you will do the normal things needed to kill yellow/mustard algae such as get behind light niches, under ladders, put in cleaning nets and poles, etc. since this algae likes to hang out in shady areas.

    It sounds like this combination has the least side effects, is of reasonable cost, and achieves the goals I was looking for. Please let us know how it works out. Normally we don't use PolyQuat for killing existing algae, but that's mostly because it takes chlorine anyway and chlorine alone can kill green algae effectively. For yellow/mustard algae at higher CYA levels, one can look at the PolyQuat as a helper to boost the kill level (as well as provide an additional mechanism for such killing) so one can use the lower "green algae" shock levels of chlorine (an FC that is roughly 40% of the CYA level).

    2nd chem geek post
    Re: High CYA Levels, Shocking, Yellow/Mustard Algae
    Thanks for the info. Was a normal shock level with an FC of 40% of the CYA level done, waiting 24 hours, then adding PolyQuat and then bringing up to shock level again? That's really the combo I'm looking at. PolyQuat by itself or at normal chlorine levels isn't going to cut it for killing existing yellow/mustard algae.
    Last edited by jfinlay; 07-13-2016 at 08:06 PM. Reason: additional information
    Jim
    Gambrills, MD

    25K Gal, Sta-Rite System 3 Cartridge, In ground, Pebble-Tec, Auto Pilot SWG, RC-42 Salt Cartridge, 3 boulder waterfall

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    borjis's Avatar
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    Re: CYA Levels, Shocking, Yellow/Mustard Algae

    3-5 chlorine at a cya of 60 is insufficient....4 is the absolute Minimum for a cya of 50.

    Polyquat isn't going to help at all once you have algae, it's a preventative....

    Reading the SLAM article should help.

    At a CYA of 70 with Mustard outbreak I had last year I was shocking to 35-37 if i recall.
    Took tons of bleach...you gotta go by the SLAM guide, no guessing if you can do less.
    16x32 IG Vinyl, 13,000 Gals. Hayward S-244T sand filter, SP2810X15 pump
    (1.5 HP motor) Raypak PR266AEN (266k btu) gas heater. TF-100 Test Kit.
    Dolphin E10 Cleaning Robot.

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    Re: CYA Levels, Shocking, Yellow/Mustard Algae

    Quote Originally Posted by borjis View Post
    3-5 chlorine at a cya of 60 is insufficient....4 is the absolute Minimum for a cya of 50.

    Polyquat isn't going to help at all once you have algae, it's a preventative....

    Reading the SLAM article should help.

    At a CYA of 70 with Mustard outbreak I had last year I was shocking to 35-37 if i recall.
    Took tons of bleach...you gotta go by the SLAM guide, no guessing if you can do less.

    Pool School Charts with SWG show the following:
    SWG Pools

    CYA (Stabilizer) Minimum FC Target FC Shock FC
    60* 3 4 24
    70 3 5 28
    80 4 6 31



    Still curious about the 40% of CYA shock, wait 12-24 hours, major Polyquat 60 dose, wiat 8 hours and another 40%CYA shock that I referenced from a 6 year old thread
    Jim
    Gambrills, MD

    25K Gal, Sta-Rite System 3 Cartridge, In ground, Pebble-Tec, Auto Pilot SWG, RC-42 Salt Cartridge, 3 boulder waterfall

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    borjis's Avatar
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    Re: CYA Levels, Shocking, Yellow/Mustard Algae

    ah I was looking at poolmath but didn't see the SWG of 3 for cya 60.

    again the polyquat isn't going to help, you'd be wasting it by putting it in.

    just do the slam and brush the entire pool once or better yet twice daily
    with the pump running 24/7 and the main drain open if you have one to
    help clear the water quicker.

    I did the mustard slam right after I saw some by the steps and it took
    a full two weeks to get rid of it all.
    16x32 IG Vinyl, 13,000 Gals. Hayward S-244T sand filter, SP2810X15 pump
    (1.5 HP motor) Raypak PR266AEN (266k btu) gas heater. TF-100 Test Kit.
    Dolphin E10 Cleaning Robot.

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