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Thread: Algae Returns

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    Exclamation Algae Returns

    We ended up slamming our pool 3X last year and I wanted to make sure we didn't have a repeat performance this year!

    Our pool has been open only 2 weeks and I've been testing the levels regularly.
    FC 7 Ph 7.3 CYA 70 TA 100

    Two days ago the FC was at 4 so I added 96 oz of bleach. I didn't test it yesterday, but when my kids went to get in the pool today, there was a green film and patches on the bottom! Ugh!!! I tested it today and the FC was 6.5. What am I doing wrong? I don't want to face the same problem again!
    Above ground pool, 15,200 gallon, cartridge filter, use a clear solar cover

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    DaninFLA's Avatar
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    Re: Algae Returns

    You need to SLAM your pool, this is NOT a one time shock like the pool store says. you need to completely sanitize and kill all algae in your pool.

    first things first, where did those test results come from? pool store, home test?
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Algae Returns

    Welcome to TFP,

    I'll be blunt, but don't mistake it for being rude. The answer to your question is that you are letting the free Chlorine slip too low, and or too often. It's really that simple. Why did you have to SLAM three times last year? Same reason. You need to do it once more, to the letter, and keep vigilant about the FC from there on out. If you do, problem solved, I promise.
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    Re: Algae Returns

    Home test, with the TF-100 kit

    - - - Updated - - -

    Last year, I was keeping the FC closer to 3 and I believe that is why I was having the problem. However, this year the FC hasn't gone below 4 so how can the algae grow when I'm keeping it typically at 7 or 8? It's very frustrating and disappointing for the kiddos.
    Above ground pool, 15,200 gallon, cartridge filter, use a clear solar cover

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    DaninFLA's Avatar
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    Re: Algae Returns

    your problem is FC. for your CYA of 70, the minimum is 5pm and the target is 8. if you had time where FC is lower than that 5 number then algae started to grow. if you then raise your FC up to the target or minimum, your playing a losing battle of killing/sanitizing vs the very quick reproduction of algae...so even when your FC is back above the minimum, its not enough to overtake the reproduction of the algae.

    you are going to have to SLAM again unfortunately, but it should be pretty quick. after that you need to keep your FC up. if you are keeping your FC near the bottom limit of 5 you are just asking for trouble by not giving yourself a buffer. at a minimum keep your FC at the 8 number, so if you have more consumption one day, or miss one day you aren't falling below that 5. personally I keep my FC above the target number and have no issues with water comfort. remember its safe to swim if below shock level. I would aim for FC of 9 to be safe...after the SLAM of course.

    CYA is a bit high, if you have the opportunity to do a partial drain I would do that. lowering your CYA down to 50 will make SLAM easier and have a lower FC number to maintain.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Algae Returns

    Quote Originally Posted by jridner View Post
    Home test, with the TF-100 kit

    - - - Updated - - -

    Last year, I was keeping the FC closer to 3 and I believe that is why I was having the problem. However, this year the FC hasn't gone below 4 so how can the algae grow when I'm keeping it typically at 7 or 8? It's very frustrating and disappointing for the kiddos.
    What is your Cya?

    Wait, sorry, you said 70 up there. Going to 4 or below is no good for 70. I'll bet you've been lower more than You think. Somewhere along the way, you have.
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    Re: Algae Returns

    Patrick & Dan have you covered. FC too low for your CYA level. I second Dan's idea to do a partial drain/refill to get he CYA down to 50.

    Here is the Chlorine/CYA Chart. To avoid algae you gotta stay above the minimum all the time!
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Algae Returns

    How is your pool water circulation? A deficient circulation will result in recurent algae boom as part of the water may be low in chlorine. Is your return jet directed down? If not you may have a seperation layer (cold water on the bottom and warm water on top) and the cold lower part of the pool is deficient in chlorine.
    South of France inground rectangular 17k pool - ruber membrane. Sliding dome, black thermal blanket covering 75% of the pool surface. Aqualux 3/4Hp pump, glass media sand filter, Zodillac robot, 110W UV-c lamp, Hayward brominator, Caliente 12kW heat pump.

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    Re: Algae Returns

    Thanks everyone for the replies so far -

    I'm going to chime in here, because I am the OP's other half (please notice that I did not say "better half," as that always refers to her). My better half is doing all the work in keeping up the pool this season, as I am currently going back to school full-time while working about 50 - 55 hours a week in my job. Admittedly, she has always done most of the chemical distribution since she is home more in the day, but cleaning and testing have been shared between the 2 of us in the past. Why we are so frustrated is that we do feel that we are following all BBB processes, and this keeps coming back in some shape or form. Of course, many (if not all) of you could easily say that we are doing something wrong because if we weren't then we wouldn't be having these issues.

    I'm a network engineer, and most of my work time is spent in solving problems. This works for me because my personality tends to want to do this with anything that might not be working - whether it be at work, home, vehicles, appliances, etc. I'm not one to want to give up, but my frustration level starts rising and my patience level starts falling when I've made multiple attempts to solve something and it keeps coming back at me. In the first year that we opened the pool, we had an algae incident about mid-way through the season (in Michigan, that translates to mid-July for us). We were still fairly green (bad pun) to the BBB method, and found that we weren't adding enough stabilizer to keep the chlorine levels as high as what they needed to be. The second year, same thing due to the same problem - didn't get enough stabilizer in before chlorine ran to 0, and the algae showed up again (this time a little earlier). The 3rd year, we kept good levels on everything and still ended up having one instance of algae - though later in the season. 4th year is when we needed to replace the solar cover - our first cover was a heavy-duty blue/black cover that served us well. I decided to go with a heavy duty clear diamond pattern cover because of how much better/efficient it seemed to be. Here is where our algae problems really starting escalating. I'm not saying the cover is the cause, but am merely indicating that it was the same season where we had multiple algae incidents (3) in one season.

    In EVERY instance of algae, we have followed the shock method to the letter of the law - we did not stop until the overnight drop test was less than 1. We'd keep good levels after that, and within 3 weeks the algae would be back. One could say that we never got rid of it but I don't know how that is possible when we were getting less than 1 FC drop overnight. We were spending so much time shocking, testing, and analyzing that we didn't get hardly any time to use the pool. So, herein is where my frustration lies - if we can't solve this, then there is really no point in continuing to own and operate the pool. Why pay the money in extra electricity usage and bleach if all you're going to do is use the pool a few times between shock sessions?

    I feel we have some variables to investigate and/or eliminate from the equation. I do think the solar cover could be a possible contributor to the problem. The problem definitely was never this bad until we replaced the cover. Granted, we do store the cover in our basement when the pool is winterized, but the cover is rinsed and dried before I completely cover it with 2 90 gallon trash bags and throw it in our basement. The ladder could also be a suspect. We have a 2-rail tiered step ladder that seems to have 5x the concentration of algae underneath it than the rest of the pool floor. I realize that water circulation is probably the weakest there, but the ladder does have a fence-like pattern in its design to allow water circulation behind the steps. Just not sure if there is something that we need to be doing with the ladder before and/or after it is put into the pool each season for use. I do spray it off with a hose before putting it into the pool, but don't know if I should be applying bleach to it to kill anything that doesn't get blown off from the hose. A 3rd culprit could be the return hose. All the plumbing used to be PVC, but last year I had to go back to a flex hose on the return line due to the underwater pool light (that was part of the return) breaking over the winter. I didn't know if there was a chance that the flex line could be holding algae in the ridges - even after the pool had passed the overnight drop test. The last variable I can think of is that we've had, I don't know, about 4 inches of rain in the last 2 weeks. Jen has kept the FC higher than what we have in the past (more in the middle of the range for our pool) and she's not let the FC get below 5 - even with all the rain. I don't know if the rain could contribute to the issue - even with our FC staying above 5. Jen hadn't been the full test for CC's the last few days, but we'll have updated numbers today.

    I don't want anyone to get the wrong perception or impression in what I'm trying to present here. Am I insisting that I have done everything correctly? No way. Am I willing to admit that I could be doing something wrong or not doing something that I need to? Absolutely. Am I willing to admit that there's probably a lot I still need to learn? You bet. However, both of us have given this our best so far and it's kicked our butts. Just my personality alone wants to know what the source of this issue is - whether I'm the one to correct it or not.

    So, I'll speak for both Jen and I when I say that we are tired, frustrated, and just not sure if we're going to find a light at the end of the tunnel that does not have a green hue to it. I know that we are grateful for any opinions, insight, experience, and expertise that could be offered here in an attempt to help us out.

    Thanks for reading (if you made it this far), and thanks in advance for any help you could offer,

    Todd
    15,000 Gallon Aqualeader Sentinelle 24x54
    AO Smith Hi-Flo 1.5 hp 2-speed pump
    Waterway Clearwater II 150 sq ft cartridge filter
    BBB, TF-100 Test Kit

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    DaninFLA's Avatar
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    Re: Algae Returns

    well that was a very long post

    not being rude, but you are trying to make excuses for the algae coming back. your an engineer (and so am i btw), and the answer to most problems is usually the simplest. This really isn't a difficult issue. your FC dropped below the minimum for your high CYA level. doing that started an algae bloom, once it starts, its too late. raising your FC a couple of ppm isn't going to kill it back to zero. the only way to keep algae out of your pool is to keep it from starting. the only way to do that is to make sure your FC is above the minimum. you said it wen to 4. the minimum is 5. so you went below.

    the TFP method works, but it requires you to stay on top of that chlorine.

    Do the SLAM as we suggested. this resets your pool and its sanitized. then keep your FC higher. don't try to keep it so close to the minimum and you wont have to SLAM ever again. take my suggestion and keep it at the top/target amount after the SLAM. a little bit higher FC level isn't going to hurt you or be noticeable. yes it will cost a tiny bit more per day due to higher levels, but its also going to keep you from getting frustrated.

    you sound really frustrated, and im sorry for that. but trying to find a bunch of other reasons for the algae outbreak is mis-directed. the answer to 99% of the questions on this forum related to algae outbreaks is...chlorine, well a lack of it at least.

    you mentioned algae on your ladder. that's a common place for it to hide. when you do your SLAM you need to remove that ladder and give it a good cleaning and let it dry out. if you are seeing algae on the ladder...its too late. algae has started.

    do the SLAM, keep your FC higher than the target and maybe take that ladder out every few weeks and clean it.

    don't give up.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Texas Splash's Avatar
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    Re: Algae Returns

    Ditto to what Dan just said. Don't over-think it so much. Use the Chlorine/CYA Chart (link below) during and after your SLAM and you're set!
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: Algae Returns

    Quote Originally Posted by jridner View Post
    Two days ago the FC was at 4
    your looking for the problem and the answer is right there.

    - - - Updated - - -

    Quote Originally Posted by jridner View Post
    I tested it today and the FC was 6.5.
    your target FC for your CYA is 8...so raising to just 6.5 is a mistake.

    you are trying to keep your FC too close to the danger zone. help yourself. go to 8, or 9, or 10.

    After the SLAM that is.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Algae Returns

    Dan, appreciate the candor and I'll take it on the chin. I wasn't trying to make excuses, and am sorry that it was perceived that way. While the BBB process appears simple, I think one of our early problems is that we were looking at it too simply. We thought we were following the processes, and we really weren't - at least while thinking we understood everything and we really didn't. I will plan on going back to pool school (while doing my other schooling) and read up on things again - especially CYA levels and how they can fluctuate and change the FC requirements.

    Removing the ladder is a bit of a pain, which is why it's only done at opening and closing. It's screwed into the top pool railing, which is actually underneath the lip of our decking. I normally am in the pool when I put the steps in and take them out, but will see if I can work something else out in removing them. I'll remove them for the SLAM, but will not be too crazy of removing them periodically unless you definitely know there will be a benefit in prevention from me doing so.

    Thanks again for taking the time to help,

    Todd
    15,000 Gallon Aqualeader Sentinelle 24x54
    AO Smith Hi-Flo 1.5 hp 2-speed pump
    Waterway Clearwater II 150 sq ft cartridge filter
    BBB, TF-100 Test Kit

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    Re: Algae Returns

    Todd, and Jen, trust me when I say that no one here means to make you feel berated in any way. My words, not yours, just know that ok? We mean well, and I promise you, it's just that you've been low on FC. You may not have killed all the algae on previous SLAMS, but based .on the info you've given, I really think it boils down to simple slip-ups on maintaining good FC consistently. I honestly believe that's all, and if you don't do that any more your light in the tunnel will come on and burn brightly from there forward.
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    Re: Algae Returns

    Quote Originally Posted by Tru-Blu View Post
    Dan, appreciate the candor and I'll take it on the chin. I wasn't trying to make excuses, and am sorry that it was perceived that way. While the BBB process appears simple, I think one of our early problems is that we were looking at it too simply. We thought we were following the processes, and we really weren't - at least while thinking we understood everything and we really didn't. I will plan on going back to pool school (while doing my other schooling) and read up on things again - especially CYA levels and how they can fluctuate and change the FC requirements.

    Removing the ladder is a bit of a pain, which is why it's only done at opening and closing. It's screwed into the top pool railing, which is actually underneath the lip of our decking. I normally am in the pool when I put the steps in and take them out, but will see if I can work something else out in removing them. I'll remove them for the SLAM, but will not be too crazy of removing them periodically unless you definitely know there will be a benefit in prevention from me doing so.

    Thanks again for taking the time to help,

    Todd
    cool Todd, yeah get it out during the SLAM for sure. if you are able to access all around the ladder maybe you wont have to take it out every month. when I had an above ground pool growing up, I would dive in with a brush and clean out the nooks and crannies once a week. you could do that too, plus its another excuse to go swimming

    I don't think you were making it too simple. this method really is that simple, but it does take dedication to dose chlorine daily to keep chlorine levels up. other than that, maybe some muriatic acid every once in a while to lower pH.

    I test my FC about twice a week and pH once a week....but but that's after the pool went thru the full SLAM and learning how my pool operates. For a while, daily FC tests are a good idea.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Algae Returns

    Thanks again, Dan and Patrick - really appreciate all your help. Also thanks again to everyone who replied. We'll be sure to report back with our status after the SLAM has been completed.
    15,000 Gallon Aqualeader Sentinelle 24x54
    AO Smith Hi-Flo 1.5 hp 2-speed pump
    Waterway Clearwater II 150 sq ft cartridge filter
    BBB, TF-100 Test Kit

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    Patrick_B's Avatar
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    Re: Algae Returns

    No sweat! Let us know if we can help.
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    Re: Algae Returns

    Todd, where abouts in Michigan are you? I'm in GR.

    First thing, if you haven't already, I promise it will only take you exactly two seconds to click on the cya:FC link in my sig, scan it, and see that this is the missing piece -- the RELATIVE nature of chlorine:cya for efficacy.

    In my pool, at a cya of 40, I bump that up one (I get a lot of debris from my forest...am by the river), so if my min is 3, I dose to 8 each morning to always ride above 4.5-5 assuming my danger zone is 4.

    This approach covers me for other variables, like the + or. - accuracy range of cya test which can be 10 ppm or more. I will usually be up a good bit from my min. The next morning, so I add less but go back to 8, assuming its possible to lose up to 50% from the sun (usually actually more like 30%)

    For water aesthetics, I also use borates each season, which may also mildly reduce inclination to algae. Just an option for consideration

    Hope those tips help. Sendin ya the mitten mojo for clear water and summer fun!
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