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Thread: Black Algae - uncertain about what to try now

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    Black Algae - uncertain about what to try now

    Our white plaster pool (newly re-plastered May 2007) has developed black algae and I have been fighting it for more than a week only to have it slowly but surely progress. I just found your board today and hope you can give me advice I can count on. Every time I go to the local Leslie's I get sold something and told slightly different things - none of which are working.

    I read through several of the threads about treating black algae but am still uncertain what to do next since my particular situation doesn't seem to have been covered.

    I have a IG irregularly shaped pool (about 15,000 gal) with a new 4 cart filter and pump and Jet Vac sweep with new pump. I discovered the black algae on a seat in the pool after I had been laid up for 3 weeks following surgery. My family was supposed to be taking care of the pool but admitted that they hadn't done anything except sometimes filling the floater with chlorine tabs when someone noticed it was empty. Arggh. No brushing, no testing etc.

    I realize that this alone perhaps should not have allowed black algae to start but when I took my water in to be tested I discovered that my CYA was at 220+. The manager at Leslie's said I was the victim of the recent widespread wildfires in our area which left tons of debris in the pool from the smoke and ash. According to him this was almost certainly the cause of the high CYA, may have dumped the black algae spores into the pool and combined with the poor care led to my problem. I had cleaned out all the debris from the smoke/ash and cleaned the pump but didn't think to check my water levels beyond the basic FC, TC and pH because the pool was crystal clear once I'd done that.

    First I shocked the pool and added Black Algaecide thinking this would take care of it. Brushed the pool with my regular brush cause I didn't know about using a SS brush. The chlorine levels went up beyond my test kits ability to measure and pH was 7.6. 2 days later took a water sample to Leslies and that's when I found out about the high CYA level and need to use a SS brush. They advised draining half the water out to lower CYA level otherwise I would never get rid of the algae. So we drained half the pool and added new water. Brushed with the SS brush till my arms were falling off. New black spots appearing here and there in shallow end.

    Day after drain/refill new water test showed CYA at 100 which Leslie's said was OK. Chlorine levels above 5 which Leslies said was good, all other levels were OK according to Leslies. Sold me more Black Algaecide and told me to treat with this. Went back 2 days later for new water test. CYA was 70, Chlorine was down to 4 despite daily shocking, pH at 7.2. New person told me I needed Chlorine levels at 20 times normal and to use 4 bags of shock then 2 bags daily for as long as it took combined with brushing. Also told me to keep pH at 7.2 as this would make chlorine work better. So I went home and did that.

    This seemed to stop the progression for a day but then I had to go out of town for one day and wasn't able to brush or tend the pool that day. I did shock it in the evening when I got home.

    Next day - more algae! I am tearing my hair out plus I am not physically able to keep doing vigorous brushing on a daily basis. So back to the store. This time my test results were: FC and CC - too high for him to get a result, pH 7.0, TA 40, CH 280 and CYA 50. New guy says I need to add Fresh Clear to get rid of "bad" chlorine. Also need to bring pH up with Soda Ash and says I need better test kit. Sells me the Leslie's deluxe DPD test kit and says I just can come to the store for the tests it doesn't cover. I'm running out of money to tackle this problem so I took the test kit and went home.

    Added 5 # soda ash, brushed and went to bed. I have been keeping the pump running almost continuously this entire time and running the sweep for several hours a day. Daily high temperatures here in Sacramento have varied between 104 to 95 during all this time. I cleaned the filter before doing the supershock with the 4 bags of shock.

    I have been using the new test kit the past 2 days. Yesterday my chlorine levels were too high for the kit to measure, TA was 100, pH was 7.2. 24 hours later my FC is about 3, CC is about 5, TA is 100, pH betwen 7.2 and 6.8. Found more black spots in deep end this afternoon.

    I am planning to add baking soda tonight to bring up the pH levels. Then shock the pool again.

    No matter how much I brush the original spots are not going away at all and slowly we are getting more and more spreading from the shallow end to the deep end. The pool water is crystal clear and the latest advice from Leslie's is to give up and have my newly plastered pool acid washed.

    Help?

    Patricia
    15,000 gal IG, Cart Filter, White Plaster
    17,000 gal IGP, White plaster, Hayward Swimclear Cartridge Filter system, Sta-Rite Max-e-pro 1/2 hp pump; 3/4 hp booster pump

    Sacramento, CA

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    JasonLion's Avatar
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    Re: Black Algae - uncertain about what to try now

    You need to get your CYA level down, preferably to around 50. It would also be a huge help to have a real test kit. I recommend a kit from TF Test Kits, see the link in my signature. The Taylor K-2006 is also a good choice. Without those two things you are more than likely wasting your time.

    The next thing you need to do is to look at how your CYA level got so high. CYA does not come from smoke and ash from fires. It comes from using "stabilized" chlorine products like trichlor and dichlor. If you continue using those products your CYA level will continue to climb and you will again have problems.

    Black algae is no fun at the best of times. We can explore ways you can fight it without brushing constantly, but only if you take the first two steps I listed above, lower CYA and get a good test kit.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Black Algae - uncertain about what to try now

    My CYA level IS down to 50 according to yesterday's testing that Leslie's did for me.

    I can't address the question of whether the weeks of soot, ash and smoke we have endured contributed to the high CYA levels - I'm not a chemist. It's a moot point for now. The level is down where you say it should be. Now that I understand how important it is to keep it there I will definitely be monitoring it much more closely in the future.

    The $30 test kit was all I could afford and the Leslie guy insisted it was all I really needed. They wanted almost $100 for the big test kit like the one you recommend and I have to feed my kids with that money this month. I will get the better kit when I can afford it. Until then I will have to make daily treks to the pool store 4 blocks away to have my water tested for now.

    If it wasn't the soot/ash/etc. then it must have been the tablets we are using in the floater. The shock we have is not trichlor/dichlor. Once we have the situation with the algae resolved then I can figure out how to manage this issue but for now I am not using the tablets.

    So any advice you can offer given the circumstances I have to work under right now would be greatly appreciated.

    Thanks,

    Patricia
    15,000 IG Cart filter white plaster
    FC3
    CC5
    TA100
    pH 7.2
    CH 280
    CYA 50
    17,000 gal IGP, White plaster, Hayward Swimclear Cartridge Filter system, Sta-Rite Max-e-pro 1/2 hp pump; 3/4 hp booster pump

    Sacramento, CA

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    frustratedpoolmom's Avatar
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    Re: Black Algae - uncertain about what to try now

    Quote Originally Posted by rlsnights
    My CYA level IS down to 50 according to yesterday's testing that Leslie's did for me.

    I can't address the question of whether the weeks of soot, ash and smoke we have endured contributed to the high CYA levels - I'm not a chemist. It's a moot point for now. The level is down where you say it should be. Now that I understand how important it is to keep it there I will definitely be monitoring it much more closely in the future.

    The $30 test kit was all I could afford and the Leslie guy insisted it was all I really needed. They wanted almost $100 for the big test kit like the one you recommend and I have to feed my kids with that money this month. I will get the better kit when I can afford it. Until then I will have to make daily treks to the pool store 4 blocks away to have my water tested for now.

    If it wasn't the soot/ash/etc. then it must have been the tablets we are using in the floater. The shock we have is not trichlor/dichlor. Once we have the situation with the algae resolved then I can figure out how to manage this issue but for now I am not using the tablets.

    So any advice you can offer given the circumstances I have to work under right now would be greatly appreciated.

    Thanks,

    Patricia
    15,000 IG Cart filter white plaster
    FC3
    CC5
    TA100
    pH 7.2
    CH 280
    CYA 50
    Hi there....

    With a CYA of 50, you should raise your FC to a schock level of at least 20, and for Black Algae, 30 would be even better. Read about shocking your pool, in Pool School. Since you have a CC of 5, you still have a lot of shocking to do... You will need to put frequent additions of liquid chlorine in your pool, to keep the FC above 20. Letting it drop down to 3, won't kill the algae.

    Brushing is essential to kill off Black Algae; the algae has a tough outer shell that is resistant to the chlorine, so by brushing it, the shell is damaged and then the insides get exposed to the chlorine, so it can be killed. It can take several days of running with the high FC of 20 for it to start to work. You may need to add chlorine every few hours, it's very good to make sure the FC is up after dark, then the sunlight won't destroy it and it can do it's job.

    Because you need to be able to test FC up to 20 and 30, thats the main reason your test kit is inadequate, and you'll find going back and forth to the PS will get old real quick. You can order the FAS-DPD chlorine test which is what you really need right now, to supplement your current kit. TF Test Kits sells it for about $23 plus shipping. I would do that at the very least. Not being able to test that high you won't know if you actually reached 20-30, it's a guessing game, and if you come up short on the FC level, you may not make any progress.

    So good luck, hope this helps.
    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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    Re: Black Algae - uncertain about what to try now

    Thanks for the information.

    Brushing the pool is a toughie because I just can't keep it up daily due to post-mastectomy lymphedema in one arm. I will have to see if I can find someone else to do that part before I wind up in the hospital. That would really make my pool problems worse

    I will check out the test kit you suggested. Giving me the FC numbers I need to be maintaining in the pool to kill the algae was very, very helpful.

    Thanks again

    Patricia
    17,000 gal IGP, White plaster, Hayward Swimclear Cartridge Filter system, Sta-Rite Max-e-pro 1/2 hp pump; 3/4 hp booster pump

    Sacramento, CA

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    JasonLion's Avatar
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    Re: Black Algae - uncertain about what to try now

    One alternative to brushing very frequently is to use a pressure washer to clean off the black algae while the pool is at shock level.

    Getting a good test kit, such as one from TF Test Kits, see the link in my signature, will save you far more on chemicals in the long run than the kit costs.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Join Date
    Dec 2007
    Location
    Central New York
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    Re: Black Algae - uncertain about what to try now

    risnights .... Something you might consider is a wall whale brush. It fits on the end of and normal pool pole. I bought one and really like it. My pool is vinyl so I have the regular brush with nylon bristles. They use to make one with half nylon and half stainless steal and one with all stainless steal bristles, but I can't find them doing a search. Since I don't have a pool like yours, someone on the forum can tell you what kind of brush to use. Do a search and you will find them in the $25 to $30 dollar range.

    Please read this thread.
    wall-whale-t702.html?hilit=whale%20wall

    Also Leslies sells them.
    http://www.lesliespool.com/browse/Home/ ... 00/I/83025


    Hotrod30

    20 X 40 foot vinyl Borates and Salt Pool
    Rolachem Chlorine Feeder
    Hayward 27 inch sand filter with 80 lbs of pea gravel
    Jacuzzi Splash Pak SP55 DE filter in parallel
    Pentair VF3050 pump

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    Re: Black Algae - uncertain about what to try now

    Thanks for the tip about the wall whale. I will check it out - I know I can buy it at Leslies - seen it there every time I go in. And my Leslies has an 18" SS brush head so I suppose I could see if I could combine the two.

    About using a pressure washer - I have a couple questions. Since I have a plaster pool I would be worried about damaging the plaster with the force of the pressurized water. Have you actually done this on a full plaster pool without any problems? How close do you have to hold the tip of the washer to the wall to blast off the top of the algae?

    Patricia
    15,000 IG white plaster
    cart filter
    17,000 gal IGP, White plaster, Hayward Swimclear Cartridge Filter system, Sta-Rite Max-e-pro 1/2 hp pump; 3/4 hp booster pump

    Sacramento, CA

  9. Back To Top    #9
    Guest

    Re: Black Algae - uncertain about what to try now

    To get rid of the black algae you need to get your FC up to between 30-40 ppm AND KEEP IT THERE by adding liquid chlorine or bleach several times a day as the FC level drops and by brushing with a STAINLESS STEEL algae brush several times a day.
    Sorry but that's how it is. I might take a few weeks to get rid of it. You got the black algae because of very high CYA and three weeks of neglect. Period.

    While the Wall Whale brush is a great product (I use one in my own pool and recommend it to my customers) it won't really help you since you need a stainless algae brush, not a nylon brush for this. If you want to get the SS brush and attack the whale wall to it it could help but make sure the stainless brush has screw holes that match up with the Wall Whale.

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    Join Date
    Dec 2007
    Location
    Central New York
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    Re: Black Algae - uncertain about what to try now

    This is what I was thinking of.





    Picture taken from this site.
    http://www.wallwhale.com/productline.htm


    Professional Grade 18" with Stainless Steel Wire Bristles
    Recommended for the Service Professional and homeowners with Exposed Aggregate finishes or severe algae problems. Do not use on vinyl or fiberglass pools or for routine brushing of any pool surface. Available through Pool Supply Branches Worldwide and directly from GABco Products.
    Hotrod30

    20 X 40 foot vinyl Borates and Salt Pool
    Rolachem Chlorine Feeder
    Hayward 27 inch sand filter with 80 lbs of pea gravel
    Jacuzzi Splash Pak SP55 DE filter in parallel
    Pentair VF3050 pump

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