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Thread: Auto-vacuum use during SLAM?

  1. Back To Top    #1

    Join Date
    May 2014
    Pearland, TX (Houston area)

    Auto-vacuum use during SLAM?

    Early last summer, after my pool was already up and running, I decided to switch from DE media to cellulose fiber media, mostly out of curiosity. I had done my research, and understood that I couldn't use most of the additives (algaecide, etc.) since their intended binding effect could cause a quick pressure build-up in the filter. Since I had no problems over the course of the year, this was not something about which I had to think further.

    I don't leave my pump/filter running in the winter/spring, because I don't use it much then, and thanks to the mild winters here in southeast Texas combined with a lack of trees and other debris sources near my house, I generally don't have problems. As long as I have it running by the time the temps are maintained in the 80s, I'm usually in good shape. In the rare cases when algae problems developed, I always found that a combo of Yellow Out and cal hypo as directed by my local pool store would take care of it quickly.

    Well, while I was out of town for 2 weeks at the end of April, the temps uncharacteristically spiked from the 70s to the 90s, and I came home to a dark green pool. With my knowledge of cellulose, the first thing I did was research recovery options that don't require algaecide and other additives, and that led me to this site. I read Pool School and some of the forums (especially Turning Your Green Swamp Back into a Sparkling Oasis). That left me with a decision: keep the cellulose and try the SLAM method with liquid chlorine, or switch my filter back to DE media and use Yellow Out/cal hypo. I decided to give the former a try. I ordered the TF-100, and waited for it and a free weekend to arrive so I could start the process correctly.

    So, here I am, 10 days into the process. I'm on the 11th gallon of liquid chlorine and 4th bag of cellulose. Today the overall color finally graduated from green to milky grey. CC has dropped from 1.5 to 1.0. Despite daily backwashing, I found the time between backwashes decreasing such that I've opened the filter and cleaned the grids three times (a task I used to have a pool company do each spring, but now I can put it on my DIY list!).

    My questions to the forum:
    1) Can I at some point put my Barracuda into the water to help with picking up dead algae from the bottom? It seems logical to me that the Barracuda plus brushing would be more efficient than brushing alone. However, the Barracuda user's guide clearly states not keep it in the water when shocking the water.
    2) Days 1-3 required a lot of chlorine to maintain the FC. Days 4-7 required very little. Days 8-10 required a lot again. I was getting nervous around Day 7 because the lack of chlorine use, in combination with a lack of improvement in the overall color (still dark green), made me think the chlorine wasn't interacting with the algae and that the treatment had somehow reached a plateau. But I was patient, and saw significant improvement the last three days. Are these non-linear trends typical?

    Current measurements:
    FC 18
    CC 1.0
    CH 425
    TA 80
    CYA 40
    pH before SLAM started 7.2-7.6

    Thanks in advance for any advice.

    P.S. The makers of TF Test Kits must be engineers, scientists or technicians. It made me smile to see - and I sincerely appreciated - the directions to multiply by 0.5. Most layperson directions would say to multiply by 1/2 or divide by 2...not use decimals.
    16k gallon, 1.5hp Hayward Super II, 48 sqft DE filter using cellulose fiber, Pentair 320 in-line chlorine feeder, Barracuda G3, TF-100

  2. Back To Top    #2
    Melt In The Sun's Avatar
    Join Date
    Oct 2009
    Tucson, AZ

    Re: Auto-vacuum use during SLAM?

    Welcome to TFP!
    Well, if the Barracuda's manual says don't do it, I'm not gonna tell you to

    SLAM progress can be unpredictable, as you've seen! Keep at it and you will have a clear pool.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

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