I have the start of black algae in my SWG pool. Noticed on the Baja step under about 18" of water. A little bit on the first step down, but don't think I have any on the walls or bottom of the pool. I've read through a number of threads here and think I have a plan. I will admit I went to the pool store first, and for this I apologize. I think I stopped with their process early enough to do it the right way. I've been using Pool Math for over two years and love it.
Pool details:
The pH is probably wrong because I tested after adding the shock. I know it wasn't 7.2 so wondering if I need to add some acid.
I spent an hour or so scrubbing the black algae spots with a stainless steel brush and it looks 90% better. I will continue to scrub until I don't see it anymore, but it is a bit confusing as some of the aggregate makes a dark spot.
I did NOT add the Hasa Algae-Ban after I read it will bleach the plaster. I don't know why the pool store would sell me something that would damage my plaster, but maybe I should know better.
CYA is always a challenge to keep up because my dog swims about 2-3hrs every day. Salt also decreases faster than it should due to the dog, but moves slower.
The way I understand it is to keep the FC level high until all black algae is gone. Seeing as it's already 90% gone, how much longer would you expect?
I also always deal with a little brown algae and now wondering if I should keep my normal FC levels a little higher?
One other aspect to consider, is I never had algae problems until the pool company did an acid/polish twice to try to fix a bad plaster install. From day one, the plaster has been ugly. It was put in when it was 112F outside and I think it's damaged. Anyway, the issue is the acid washes have left the surface pitted and not smooth. I think that's giving the algae a place to grab on and hide from my brushing. Still fighting with the pool company to replace the plaster, but with covid, it might be a while.
I should also point out the water was crystal clear when I started.
Pool details:
- About 20,000 gallons
- Pebbletec Pebble Fina grey finish
- Hayward SWG system with cartridge filter
- FC: 18.0
- CC: 1.0
- pH: 7.6
- TA: 100
- CH: 250
- CYA: 45
- Salt: 2800
- Temp: 79F (night temp)
The pH is probably wrong because I tested after adding the shock. I know it wasn't 7.2 so wondering if I need to add some acid.
I spent an hour or so scrubbing the black algae spots with a stainless steel brush and it looks 90% better. I will continue to scrub until I don't see it anymore, but it is a bit confusing as some of the aggregate makes a dark spot.
I did NOT add the Hasa Algae-Ban after I read it will bleach the plaster. I don't know why the pool store would sell me something that would damage my plaster, but maybe I should know better.
CYA is always a challenge to keep up because my dog swims about 2-3hrs every day. Salt also decreases faster than it should due to the dog, but moves slower.
The way I understand it is to keep the FC level high until all black algae is gone. Seeing as it's already 90% gone, how much longer would you expect?
I also always deal with a little brown algae and now wondering if I should keep my normal FC levels a little higher?
One other aspect to consider, is I never had algae problems until the pool company did an acid/polish twice to try to fix a bad plaster install. From day one, the plaster has been ugly. It was put in when it was 112F outside and I think it's damaged. Anyway, the issue is the acid washes have left the surface pitted and not smooth. I think that's giving the algae a place to grab on and hide from my brushing. Still fighting with the pool company to replace the plaster, but with covid, it might be a while.
I should also point out the water was crystal clear when I started.
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