I've noticed a black sticky substance. It's only in the grout lines on the corners of my pool and is slightly above the waterline (probably partially below the waterline at times depending on water level). It's only in the corners of my pool on the grout line between the tiles. I've ordered a small wire brush to clean it, but should I be concerned about it? Not sure what it could be.
What is this?
- Thread starter st47
- Start date
It could be black algae since there isn't much turbulence in the corners but the bigger question is what are you pool chemistry levels and how are you testing.
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Salt Water Pool
7.6 ph
80 TA
70 CYA
9 FC
CH 310
Salt 3300
I am testing using a mix of different items. I have a taylor 1005 kit, and then added fas-dpd to it because the 1005 dpd test wasn't accurate enough. Then I added the larger bottle and view tube for CYA so I could test more accurately. I use aquacheck test strips for Salt, which seems pretty accurate and doesn't use color coding like most test strips do.
I try to keep my FC around 7. I find if I get to 5 I get some stuff on the walls that when I brush off makes dust in the pool. Not sure what it is...but everything else seems fine. I lose 1 ppm FC with the OCLT and have 0 combined chlorine.
7.6 ph
80 TA
70 CYA
9 FC
CH 310
Salt 3300
I am testing using a mix of different items. I have a taylor 1005 kit, and then added fas-dpd to it because the 1005 dpd test wasn't accurate enough. Then I added the larger bottle and view tube for CYA so I could test more accurately. I use aquacheck test strips for Salt, which seems pretty accurate and doesn't use color coding like most test strips do.
I try to keep my FC around 7. I find if I get to 5 I get some stuff on the walls that when I brush off makes dust in the pool. Not sure what it is...but everything else seems fine. I lose 1 ppm FC with the OCLT and have 0 combined chlorine.
I just noticed the advice about scraping a little off and rubbing it on white paper. I tried this and it was dark green, so I suspect it is black algae. Crazy because there is so little and it is only in the corners. Since its currently not below the waterline should I just keep my waterline a little low, brush it off and catch as much as I can so it doesn't get in the water, and the pour some bleach on it for a couple days?
Or, I could probably get about 70 percent of it in the water if I bring my waterline up to the waterline drain and then keep FC high (like 11 or so) for awhile? But I doubt I could submerge it all. It's too high.
Or, I could probably get about 70 percent of it in the water if I bring my waterline up to the waterline drain and then keep FC high (like 11 or so) for awhile? But I doubt I could submerge it all. It's too high.
I scrape it off while not letting any of it get into the water then I would ues straight bleach with brush and work in the eliminating what's left. Run the chlorine on the hot side of target +2ppm for the next 10 days. I don't think you have much to worry about. You did mention 1ppm on the OCLT but I still say no slam just the elevated FC.
Katodude
Silver Supporter
- Aug 22, 2017
- 2,620
- Pool Size
- 15000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Scrape if off, I use a wood bbq skewer to to damage anything. 10% LC in a spray bottle and then nuke it.
Sounds good. I will take care of it when my wire brush gets here tomorrow. Not sure why I didn't get concerned earlier. Its been there for months. Lucky it didn't spread anywhere else. Thanks for your advice! I appreciate it!
That's been a dead area for months which means every so often hit it with the spray bottle above mentioned and it'll never be back.