Black algae has taken over our pool. We called a company to come out and see what they would recommend to get rid of it and now we are trying to decide what is the best method. Would really love some advice. One method is draining it and pressure washing it another is just chemicals with I guess them coming back for 3 weeks? And we are in Texas, so is this the right time of year to do this? I’m attaching their estimates. Thanks in advance!
Black algae need advice please
- Thread starter hgreenleaf1
- Start date
-
- Tags
- black algae
- Jun 24, 2021
- 15,992
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
I agree with @JamesW we need picts for accurate diagnosis.
I would not us the PoolRX. Adds metals that can stain, and will not address black algae.
If we confirm black algae, the best method is to use a power washer (lower pressure the better, and wider tip, starting far away from the spots and moving in until it starts to blow the algae away). No need to drain to use power washer. Then get a pressure spray pump, fill with the strongest liquid chlorine you can find and spray the areas with the LC with the pool pump off.
You will then need to run your FC at 20% of your CYA for several weeks.
Either way, as a result of having BA, after the few weeks of FC at 20%, you probably need to run FC at 15% of CYA for life of this plaster.
www.troublefreepool.com
I would not us the PoolRX. Adds metals that can stain, and will not address black algae.
If we confirm black algae, the best method is to use a power washer (lower pressure the better, and wider tip, starting far away from the spots and moving in until it starts to blow the algae away). No need to drain to use power washer. Then get a pressure spray pump, fill with the strongest liquid chlorine you can find and spray the areas with the LC with the pool pump off.
You will then need to run your FC at 20% of your CYA for several weeks.
Either way, as a result of having BA, after the few weeks of FC at 20%, you probably need to run FC at 15% of CYA for life of this plaster.
Black Algae
This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.
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Is the pool painted?
What is the history of the pool?
If you rub your hand on the sides, does it leave a white residue?
What is the history of the pool?
If you rub your hand on the sides, does it leave a white residue?
It is not painted. No white residue. We had it replastered in 2012. Had never had this problem until recently.
It is not painted. No white residue. We had it replastered in 2012. Had never had this problem until recently.
It does not really look like black algae.
Does it brush off?
Try a full SLAM with a lot of brushing.
SLAM Process
Does it brush off?
Try a full SLAM with a lot of brushing.
SLAM Process
It looks more like gunite showing through.
Did they do a full chipout of the old plaster or did they replaster over the existing plaster?
Can you show a closeup of the plaster?
I do not see any aggregate in the plaster, which usually means paint.
What plaster mix was used?
Was it plain marbelite?
I do not see any aggregate in the plaster, which usually means paint.
What plaster mix was used?
Was it plain marbelite?
There might be some black algae.
Black algae is a type of black mold or bacteria which will scrape off and it will be like a blue/green slime mold or bacteria if you wipe it on a paper towel.
This part near the light looks like black mold/algae/bacteria.
I think that you have a lot of pitting with gunite showing through and some black algae beginning to grow in the pits.
Get a good brush and brush vigorously and SLAM for as long as it takes to remove the algae.
SLAM Process
Black algae is a type of black mold or bacteria which will scrape off and it will be like a blue/green slime mold or bacteria if you wipe it on a paper towel.
This part near the light looks like black mold/algae/bacteria.
I think that you have a lot of pitting with gunite showing through and some black algae beginning to grow in the pits.
Get a good brush and brush vigorously and SLAM for as long as it takes to remove the algae.
SLAM Process
It is hard to tell for sure.
It looks like the plaster is thin and pitting with gunite showing through.
Pitting can increase the risk of black algae developing in the pits.
I would brush thoroughly several times per day while doing a full SLAM process.
It looks like the plaster is thin and pitting with gunite showing through.
Pitting can increase the risk of black algae developing in the pits.
I would brush thoroughly several times per day while doing a full SLAM process.
Can you post all chemistry readings?
What test kit do you have?
Pool Care Basics
Overnight Chlorine Loss Test
SLAM Process
PoolMath
FC/CYA Levels
Test Kits Compared
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What test kit do you have?
Pool Care Basics
Overnight Chlorine Loss Test
SLAM Process
PoolMath
FC/CYA Levels
Test Kits Compared
Become a TFP Supporter
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