Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 6 of 6

Thread: Moss growing on pool edges but appears clean??

  1. Back To Top    #1

    Join Date
    Jul 2014
    Location
    phoenix, az
    Posts
    3

    Moss growing on pool edges but appears clean??

    Hi everyone,

    I am not sure how to fix this issue. I seem to have a dark green moss growing in some spots along my pool. Specifically, there is some in the grout along the water line. I did find moss on one if the steps a few months back but I thought I corrected it by upping my chlorine levels for a while. I'm in Phoenix so I have very little experience with moss in an otherwise dry environment. The pool is salt water. The moss spots are very small and I wouldn't have even noticed them if I wasn't right up against the wall looking at them yesterday. I can post more specific water chemistry a little later today but my chlorine, salt, and CYA are in a "good" range, alkalinity and pH are high. Does anyone have experience with this?

  2. Back To Top    #2

    Join Date
    Jul 2014
    Location
    phoenix, az
    Posts
    3

    Re: Moss growing on pool edges but appears clean??

    I tested the water this afternoon and these are my numbers:
    FC 3.5
    CC 0
    CH approx 365 (some purple "floaties" but liquid blue)
    TA 150
    CYA 30
    pH 8.2

    The FC, alkalinity, and pH are a little higher than recommended for my salt system. CYA is on the low side but still within recommended levels.

  3. Back To Top    #3

    Join Date
    May 2014
    Location
    Current: Singapore Previous: Clayton, Victoria, Australia
    Posts
    584

    Re: Moss growing on pool edges but appears clean??

    Welcome to TFP!

    How are you getting those test results?
    If those results can be believed, then you will need to lower your pH immediately. pH8.2 is the maximum reading and anything higher reports as 8.2, your pH may be much higher.
    We also recommend a higher CYA level for a salt water pool. See water balance for SWG.
    The alkalinity would come down over time as you add acid to lower your pH. See ABCs of pool water chemistry.

    Could you please post a picture of what you are seeing?

    Please add details about your pool to your signature as indicated in this post.

    I would recommend you read Pool School.

  4. Back To Top    #4
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Moss growing on pool edges but appears clean??

    Welcome!

    What she said about pH and CYA and FC levels.

    It's not moss you're seeing - it's algae. I've seen it along the grout line inside my skimmer opening once, and I never would have seen it had I not surfaced right there. It's generally above the water line, where it gets wet from waves, but it doesn't stay immersed in chlorinated water. I fixed mine by attacking it with a plastic household scrub brush. Then i raised the water level and added a couple extra PPM of bleach. It hasn't come back - and I check for it regularly now.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  5. Back To Top    #5

    Join Date
    Jul 2014
    Location
    phoenix, az
    Posts
    3

    Re: Moss growing on pool edges but appears clean??

    Hi everyone, thank you for the responses! I am using the tf-100 to get my numbers. I've been a "lurker" for a while, reading pool school and what not. I can post a picture tomorrow but I think Richard must be right. Blech. Should I SLAM once the water level is up? I am having trouble figuring out what my chlorine level should be during SLAM on a salt water pool. As far as CYA, my SWG recommends 30-60. Should I be okay going to 70 if my systems recommends a lower number? I'm afraid of over doing it
    Last edited by perrosalado; 07-23-2014 at 11:47 PM. Reason: forgot a question :)
    12,000 gallon salt water pool.
    Pebble tec.
    TF-100
    Phoenix, AZ

  6. Back To Top    #6
    northrn's Avatar
    Join Date
    May 2014
    Location
    Cincinnati, OH
    Posts
    532

    Re: Moss growing on pool edges but appears clean??

    Chlorine/CYA Chart will give you the minimum, target, and SLAM level of chlorine you need based on your CYA level. Maintain those SLAM levels every hour or two until you have no more visible algae, the water is sparkling clear, and you pass the overnight free chlorine loss test.

    Welcome
    27' AG 18K Gallons ~ Cartridge Filter ~ Pentair 1.5 HP Pump

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •