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Thread: Persistent Algae(?) Stains - help?

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    Persistent Algae(?) Stains - help?

    I'm now into my second week of SLAMming my pool and while the water looks good, I've got brown stains where the algae used to be (I can't believe that it's still algae). I reached the goal for the SLAM two days ago (<1 overnight loss, 0CC and clear water) but then I've spent the better part of past 48 hours at the mustard algae level of >30 but I'm not seeing any results and my CC is still at 0. My current numbers:

    FC: 24.5 (I've let this back off from the >30 today)
    CC: 0
    CYA: 50
    TA: 180
    CH: 575
    PH: 7.8

    I know that TA and CH are high but could that be stopping the FC from getting at the last bit of algae? The fact that I've maintained 0 CC for the past 48 hours leads me to believe that nothing is going on (apart from me adding bleach to the pool).

    The stains are streaks on the sides and on the bottom in the shallow end. The pool overall looks great but these stains are just not going anywhere and driving me crazy. Four weeks ago they weren't even there so it's not like it's a lingering problem- they just showed up, I listened to a pool guy and dumped a bunch of phosphate killer in there and then shocked but they didn't budge. That led me to the SLAM technique to finally get it sorted but no joy so far.

    Any help/suggestions are more than welcome!
    My Pool: 22,000 gal inground plaster, Hayward SP3210EE pump, Century Centrurion 1.5HP motor, Pentair FNS Plus 48sqft DE filter

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    Mr Bruce's Avatar
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    Re: Persistent Algae(?) Stains - help?

    Two thoughts. If you can adjust returns to point toward the stains that might help. A brush with some stainless steel bristles might help also. I would allow the FC to drop to "elevated", not SLAM and see what it looks like by the weekend.
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
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    Re: Persistent Algae(?) Stains - help?

    Thanks. I'm going to let the level get down to the elevated levels and maintain it there for a while and see what happens. The returns likely haven't been moved since the first Bush administration so there's no chance of them being adjusted unfortunately. I've always wondered about the stainless steel brushes but worried that i'd be doing damage to the surface. I should also mention that a couple of weeks ago, before the SLAM, I pressure washed the walls (my CYA was through the roof so I drained a good portion of the pool). I tried to loosen some of the algae up but it didn't do much. I wonder whether a SS brush would do the trick or not but I might as well give it a go.

    It's just frustrating to see everything else go according to plan (like I said, the water is great and the levels for the most part are where they need to be) but to have these lingering stains. Hopefully it sorts itself out with a bit of time.
    My Pool: 22,000 gal inground plaster, Hayward SP3210EE pump, Century Centrurion 1.5HP motor, Pentair FNS Plus 48sqft DE filter

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    Mod Squad pooldv's Avatar
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    Re: Persistent Algae(?) Stains - help?

    Put a Vit C tablet on the stain for 5 or 10 minutes and see what happens.
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    Re: Persistent Algae(?) Stains - help?

    I'll try that out. The stains are sort of elongated like streaks but i'll put a tablet in the middle and see what that does. At this point i'll try just about anything. Any idea on the science behind that?

    Thanks.
    My Pool: 22,000 gal inground plaster, Hayward SP3210EE pump, Century Centrurion 1.5HP motor, Pentair FNS Plus 48sqft DE filter

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    Re: Persistent Algae(?) Stains - help?

    Yeah, the Vit C tablet was a bit of a bad idea. It certainly whitened up the area around the stains but didn't get at the main problem. Here's hoping that the stiff brush will do the trick.
    My Pool: 22,000 gal inground plaster, Hayward SP3210EE pump, Century Centrurion 1.5HP motor, Pentair FNS Plus 48sqft DE filter

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    Re: Persistent Algae(?) Stains - help?

    Quote Originally Posted by Glenn Roddick View Post
    Yeah, the Vit C tablet was a bit of a bad idea. It certainly whitened up the area around the stains but didn't get at the main problem. Here's hoping that the stiff brush will do the trick.
    Just to clarify, are you saying that the stain itself did not change with the vitamin C? If not, you can try putting a trichlor puck on the stain for a few minutes to see if that lightens it.

    You asked earlier about the science behind the stain tests... Vitamin C is acidic and will lift metal stains. The trichlor puck will lighten/remove organic stains. The puck is also acidic though and may lighten metal stains too which is why it's better to do the vitamin C test first. Hopefully one of these tests will show results! Report back with your findings and we can move forward from there.
    11,500 Gal Fiberglass IG Pool. Hayward cartridge filter with Pentair 3/4 HP pump
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    Mod Squad pooldv's Avatar
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    Re: Persistent Algae(?) Stains - help?

    Vit C (ascorbic acid) will lift metal stains. So, if it lightened the area then there are metal stains present usually iron or copper. I assume you are on city water so that likely eliminates iron. The most common sources of copper are algaecide, mineral systems and eroded copper heat exchangers from low PH.

    More here, Pool School - Metals in the Water and Metal Stains
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