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Thread: Clear Water - Stained Plaster?

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    Join Date
    Aug 2014
    San Diego, CA

    Clear Water - Stained Plaster?

    Hi all! I have been lurking on TFP for a while as I recently bought a house with an old plaster IG pool in the backyard. After buying the house I drained the swamp water out, refurbished the equipment, acid washed, and refilled from the hose (city water). Here's some details of the pool (which I'll be adding to my sig).

    -15k gal IG gunite/plaster
    -3/4HP Pentair pump/FNSP48 DE filter

    I'm using a taylor 2006C test kit. Upon filling the pool, the water immediately had a slight green tint to it (perfectly clear though). I was concerned that it might be metals in the water. The local Leslie's assured me the city water doesn't have metals, and they were unable to test for it. My concern is that over the last month, the water has always stayed perfectly clear but the white plaster has been gradually getting yellowy-greenish staining on it. I just came back from a weekend away (raised chlorine levels) and the staining has gotten worse. I'm not sure if it's old nastiness seeping out of the plaster, or something being deposited on it. Most of it won't brush off the plaster. I've never had any algae or anything in the pool chemical levels have been kept pretty stable. Current readings are as follows:

    pH: 7.4
    TA: 140
    CH: 180
    FC: 3.0
    CC: ~0.0
    CYA: 30-40

    I haven't been adding anything other than chlorine tabs (the plan is to switch to bleach soon once I'm satisfied with the CYA levels). Hopefully the pic shows the new staining that appeared over the weekend. In addition there is a general yellow/green staining over the whole plaster surface. Unfortunately the water is so clear it makes the staining very obvious and unattractive to me!

    Does anyone have any suggestions? Recommendations on how to clean up the staining or get a metals test kit?

    Thanks in advance!!!! I've already learned a ton from this's great!
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  2. Back To Top    #2

    Clear Water - Stained Plaster?

    Most likely metal staining. I just went through the same exact thing. My water was yellow/green tinted and was filled with city water. You likely have iron and copper in your water, that's what my mix was. I used a product called metal magic by proteam and it worked great. For your size pool you would need at least two bottles of it.

    My advice would be go to a store that can test for metals and see what they say. If you have actual stains on the plaster, you can perform the vitamin c test to verify metals for yourself. Chances are that's what it is. The metal magic is @$20 for a bottle. It can be used with chlorine in the pool vs other sequestrants that want you to have very low or no chlorine.

    I'd wait for some others to chime in with their expertise, but if you want check my recent thread of my same issue. Good luck.

  3. Back To Top    #3
    Butterfly's Avatar
    Join Date
    May 2007
    South Carolina

    Re: Clear Water - Stained Plaster?

    First, with CYA 40ish, you should keep FC between 3 and 7, and never below 3!

    Do you have a tree/trees dropping stuff into the pool?

    Have you tested the stains to determine if they are organic or metals? Rub/place a trichlor tab on the stain for a couple of minutes. If it lightens, it is an organic stain. If no joy, you can test for metals stains. Rub/place a cheap vitamin C tablet on the stain.

    Can you post pic of the whole pool? Maybe we can see the overall staining you are talking about.

    Also, based on your description at new fill, I would add a sequestrant.
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    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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