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Thread: Fighting my second algea bloom in 2 years

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    Fighting my second algea bloom in 2 years

    I recently came back from vacation to discover a green swamp out in the back-yard. Apparently, either the folks who had promised to keep up the pool in my absence decided not to follow my instructions or they held frequent block parties (more plausible) in my pool. This is the second bloom I am fighting with the first one being right after we bought the house in March of 2012 (pump was out for a few weeks.) This time it is not as bad as the first time and I decided to fight it right away before it got worse.

    Anyway, I have been religiously pool-stored and my first reaction was to rush a sample to the local Aqua Quip where I parted with some $140 for 12 bags of shock (Burnout 35) and 1 bottle of copper-based algaecide. I was to use 6 bags and the algaecide and things were to clear up. My CYA was already too high (100) but they didn't tell me anything about it. After about 36hours and some slight improvement, I decided to research the bleach alternative (I came across it back in 2012 but wasn't to confident or knowledgeable about pool chemistry and thus decided to stick to pool store.) ... and that's how I came across TFP. After reading several posts, I decided to join as a member.

    I just ordered a Taylor K-2006 kit and it should be here on Tuesday (thanks Amazon Prime!) Aqua Quip wanted $130 for it but Amazon has it for $49! I have also already put in 4gals of 7.85% Clorox bleach over the last 24hrs. Costco has a 3-pack at $9.39. I saw more improvement with the bleach and I can understand why: more chlorine with no stabilizer as compared to the Burnout 35 I had previously used.

    I didn't want to just wait for the test kit so I decided to take in another water sample to Aqua Quip:
    Sat Index: 0.4
    TDS: 900
    CYA: 110
    Tot Chlorine: 10
    Free Chlorine: 10
    pH: 7.8
    Tot. Alkalinity: 153
    Adj Total Alkalinity: 153
    Tot. Hardness: 213

    The chlorine readings above are "max of what our system can handle, so you probably have more than that" according to the Aqua Quip guy.

    I know its kind of late in the season but we are still getting 85+ weather here in Seattle and as such, I want to get the pool back in usable state. I am ready to go ahead and do a partial drain (40%) in an attempt to lower the CYA. Then I will take advantage of the rainy fall/winter to do a bigger drain and lower CYA even further. My current plan is to go start the partial drain today and refill so that by the time test Kit arrives on Tuesday, I should be ready to get busy.

    Is there anything else I could do as I wait for the kit? I don't want the algae to rebloom yet I don't want to over-chlorinate (is that even possible when there is live algae?) I am also using the aquabot turbo to vacuum the junk of the floor and walls. In as much as it is picking up stuff, it is also agitating the water and making things more cloudy. (yes, I know it's not smart to have the bot in there with such high chlorine levels, but the bot wass already falling apart and I will probably replace it by next season.)
    20k gal, gunite, IG, spill-over spa; SuperFlow Sand Filter (2.7sq ft); Pentair IntelliFlow Variable Speed Pump; Teledyne Laars Lite gas heater; Aquabot Turbo robotic cleaner; no SWG;

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    Mod Squad JVTrain's Avatar
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    Re: Fighting my second algea bloom in 2 years

    Looks like you're doing all you can until the kit arrives. A gallon of bleach per day is fine and at your current CYA level, there is very little risk of damaging your robot, that is unless you're leaving the robot in the pool between cleanings. You should always take it out and clean the filters as soon as you can after it finishes a cleaning cycle.

    Go through some of the initial articles in Pool School found on the Getting Started Page and check out more of them that look interesting. Also, this post by JasonLion is a great primer and what you're about to accomplish. Turning Your Green Swamp Back into a Sparkling Oasis

    Once you get your kit, post full test results here and we'll help you get things started!
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Fighting my second algea bloom in 2 years

    Here is an update.

    The Kit is supposed to arrive today.

    I drained 1/3 of the pool are filled it up with city water. This lowered my CYA from 110 to 55. (Aqua quip did two readings and got 50 and 60 so I am averaging the two.) I also had them do a diluted FC test and they came up with FC 16 and TC 16. After those readings, I used the PoolMath calculator to determine how much more to SLAM with bleach and I ended up putting in 192oz last night. I will be taking a sample to pool store once more today if my kit doesn't arrive in the next hour or so. As of this morning, the water is looking much more clearer and I can see the bottom main drain.

    I tried to buy DE but the pool store guys were reluctant on selling it to me since they know I have a sand filter. They are totally against putting any amount of DE in the sand filter BUT are willing to sell me some cellulose DE alternative. They have 50lb bag of DE for $39 and they are selling the 9oz bag of cellulose DE alternative for $32! I don't want to buy a 50lb bag of DE since I probably need less than a pound per year and I don't want to buy the cellulose stuff since I feel its overpriced. I have tried to look around for DE but no one carries it in stock and I have to wait 3-7days at Walmart, Home Depot or Ace hardware. At this point, I am just about ready to order it from Amazon and get it in 2 days. Before I do that, does anyone have any suggestions regarding DE versus cellulose alternative?
    20k gal, gunite, IG, spill-over spa; SuperFlow Sand Filter (2.7sq ft); Pentair IntelliFlow Variable Speed Pump; Teledyne Laars Lite gas heater; Aquabot Turbo robotic cleaner; no SWG;

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    Re: Fighting my second algea bloom in 2 years

    UMMMM, find another pool store that don't know you have a sand filter... don't offer any info to the new pool store, just tell them you need DE. Its going to be their loss anyway if you go to a different store.
    From what you describe, you may not need the DE for a couple of days anyway, let the sand filter clean the bulk of the algae up before adding DE.
    Randy H.

    Intex 18' X 48"
    G.A.M.E. Sandpro 75 Sand Filter (Single Speed 3/4 HP, 75 lbs sand, 2650 GPH, 7-way valve)

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    Re: Fighting my second algea bloom in 2 years

    Welcome to TFP.

    You might also find pool DE at a lowes store in the pool section. Just don't confuse it with DE for the garden. They aren't interchangeable.
    18*36*23 true "L" vinyl IG 29,000 gallons. SWG. TF-100 test kit.
    http://tftestkits.net/splash-page.html

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    Re: Fighting my second algea bloom in 2 years

    Ok, lots of progress made today:
    I got some DE from a local pool installer. They were willing to sell me 5lbs from their own stock but when I told them I needed just wee-bit, they gave me 3lb for free.

    K-2006 kit came in today and I ran the first tests:
    FC: 17ppm
    CC: 1ppm
    pH: 7.5
    TA: 100
    CH: 140.
    CYA: 70.

    Prior, my FC was at 16 before I dumped in a 1.5g of bleach 24 hrs ago.

    The water is relatively clear and I can see all the way to the bottom. Turning on the light reveals cloudiness. Scrubbing agitates a lot of junk and makes the water cloudy. I added some DE to the backwashed filter and I am monitoring it overnight to see how it fares. I may also throw the robot back in tomorrow morning.

    I also added some Calcium Chloride Dihydrate to boost the CH levels. Pool math was recommending 22lbs but I started off with 11lb and will retest tomorrow.
    20k gal, gunite, IG, spill-over spa; SuperFlow Sand Filter (2.7sq ft); Pentair IntelliFlow Variable Speed Pump; Teledyne Laars Lite gas heater; Aquabot Turbo robotic cleaner; no SWG;

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    Re: Fighting my second algea bloom in 2 years

    With a CYA of 70, your SLAM level is 28. Using the tested level FC of 17 from the last post, you will need to add another 342 oz. (2 gallons and 3 cups) of 8% bleach.
    CYA/Chlorine chart is here
    Pool Math is here.
    I would just concentrate on getting rid of the algae completely before trying to adjust any other aspects of the pool water chemistry.
    After adding bleach and throwing your robot in to scrub the bottom, it might be a good idea to remove your light if you have one and check/ scrub that. check your skimmers for any signs of green there.
    Once you have that done, do an FC test. You don't need to do a full set of tests because getting rid of the algae is all we are concerned with at this moment. Save your testing supplies and if you notice you are getting low, please order more before you run out. Adjust FC to SLAM level if needed.
    Go back up to post #2 and read what Joel (JVTrain) suggested. There is a wealth of information contained on this site and its all yours for the taking...
    Randy H.

    Intex 18' X 48"
    G.A.M.E. Sandpro 75 Sand Filter (Single Speed 3/4 HP, 75 lbs sand, 2650 GPH, 7-way valve)

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    Re: Fighting my second algea bloom in 2 years

    Quote Originally Posted by one_knight4u View Post
    With a CYA of 70, your SLAM level is 28. Using the tested level FC of 17 from the last post, you will need to add another 342 oz. (2 gallons and 3 cups) of 8% bleach.
    CYA/Chlorine chart is here
    Pool Math is here.
    I would just concentrate on getting rid of the algae completely before trying to adjust any other aspects of the pool water chemistry.
    After adding bleach and throwing your robot in to scrub the bottom, it might be a good idea to remove your light if you have one and check/ scrub that. check your skimmers for any signs of green there.
    Once you have that done, do an FC test. You don't need to do a full set of tests because getting rid of the algae is all we are concerned with at this moment. Save your testing supplies and if you notice you are getting low, please order more before you run out. Adjust FC to SLAM level if needed.
    Go back up to post #2 and read what Joel (JVTrain) suggested. There is a wealth of information contained on this site and its all yours for the taking...
    Thanks for the feedback! However, I saw this after already running my morning tests (about 14hrs after the last set of tests.)

    FC: 17ppm (no change from last night)
    CC: 0.5ppm (was 1ppm last night)
    pH: 7.4 (was 7.5 last night)
    TA: 100
    CH: 200 (up from 140 last night due to my adding 11lbs of Calcium Chloride Dihydrate)
    CYA: 70ppm (no change)

    Water is clearer once again (I had brushed last night and it became a little bit cloudy: could still the bottom even in the cloudiness. Stuff settled overnight and filter helped too.) I backwashed last night before adding about a cup of DE. The cup of DE took my psi from 1.5 to 2.5. After running overnight with DE, I am now up to a psi of 4. I am running on my lowest set speed on my variable pump: 1200rpm. [EDIT: actually 2nd lowest setting of 1500rpm]

    Here are my observations/questions:
    1. Based on my numbers, above, I have met the 3 conditions for SLAM (FC stayed constant overnight, CC at exactly 0.5ppm, clear water) Am I correct here? What do we mean by clear water? Is being able to see bottom drain good enough? I would expect some cloudiness in the water due to the dead algae.

    2. I am toying with the idea of leaving the DE there for maybe 6-12hrs more before I backwash. Granted that I have gone from 1.5psi to 2.5psi with DE and then 4psi after 12hrs. At the low speed, I don't want to exceed 6psi. Are these safe ranges?

    3. Do I need to remove the light even with the 17ppm of FC? It was 16ppm 48hrs ago before I bumped it up by adding 192oz of 7.8% bleach (didn't have a kit to measure resultant levels then) and it has stayed steady at 17ppm for at least 14hrs overnight. I am not so keen getting into the water at such a high FC level to remove the underwater light.

    Thanks for all your help!
    Last edited by GoGi; 08-20-2014 at 12:03 PM. Reason: I actually meant 2nd lowest setting of 1500rpm.
    20k gal, gunite, IG, spill-over spa; SuperFlow Sand Filter (2.7sq ft); Pentair IntelliFlow Variable Speed Pump; Teledyne Laars Lite gas heater; Aquabot Turbo robotic cleaner; no SWG;

  9. Back To Top    #9

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    Re: Fighting my second algea bloom in 2 years

    1) No, you haven't started a SLAM, therefore you cannot say you are SLAM completed
    2) No. Our recommendation is to backwash when filter pressure increases by 25% over clean pressure.
    3) We would recommend you remove the light as our experience shows algae likes to hide behind lights.

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    Re: Fighting my second algea bloom in 2 years

    Quote Originally Posted by Abigail K View Post
    1) No, you haven't started a SLAM, therefore you cannot say you are SLAM completed
    2) No. Our recommendation is to backwash when filter pressure increases by 25% over clean pressure.
    3) We would recommend you remove the light as our experience shows algae likes to hide behind lights.
    Thanks for your response, Abigail.
    Regarding not SLAMing, the day I came back from vacation and realized I had a green pool, I took in a sample to pool store and found out I had 0 FC. I purchased and dumped into the pool 6lbs of lithium hypochlorite (Burnout 35.) By next morning, I noticed a lighter color in the pool. By that evening, there was not much change from morning so I suspected the CYA levels were high and had them measured: 110. The poolstore "maxed' their FC reading at 10ppm I decided to do a partial drain and refill and stay away from the poolstore's chlorine. I then dumped 3gals of 7.85% bleach. Next day (3rd of treatment), I was down to FC of 16ppm and CYA of 55 according to a diluted test by the poolstore folks. Based on the CYA/CL chart, I used PoolMath to calculate how much bleach I need to add to get 24ppm. I added the bleach but had no way of testing since my kit was not yet here. Kit arrived next day and I tested 17ppm FC and 1ppm CC. Overnight, I maintained 17ppm FC and dropped CC to 0.5ppm according to my morning test. This evening I tested at 14ppm FC and 0ppm CC.
    Based on the above, I believe I have done the equivalent of a SLAM. Without having the kit to measure FC myself for the three days, I used the pool store readings to get to the required FC for my CYA levels. Since I got the kit, my FC has dropped from 17ppm to 14ppm in over 36hrs while CC has dropped from 1ppm to 0ppm. Water is now clear.

    Regarding the backwash: I started with clean filter at 1.5psi. Adding DE took it to 2.5psi (with pump at 1500rpm). Over the last 2yrs, I have been backwashing when I get to about 5psi and usually get a clean pressure of around 1 - 2 psi. Should I consider the clean pressure as the 1.5psi (before adding DE) or the 2.5psi (after adding DE)?

    I will remove and clean light niches tomorrow morning.
    20k gal, gunite, IG, spill-over spa; SuperFlow Sand Filter (2.7sq ft); Pentair IntelliFlow Variable Speed Pump; Teledyne Laars Lite gas heater; Aquabot Turbo robotic cleaner; no SWG;

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    Re: Fighting my second algea bloom in 2 years

    I would advise you to raise to do an OCLT at SLAM level to be sure.

    I'll ping someone with regards to clean pressure and get back to you.

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    Re: Fighting my second algea bloom in 2 years

    Consider the clean pressure 2.5psi.

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