Unusual Algae - Please help

GuRC

Member
May 1, 2017
12
San Jose CA
Hey! I have some Brown Algae in my pool that doesn’t brush off easily with a nylon brush. It has a slimy consistency and proliferates upon low chlorine and reduces when I shock the pool. The guys at two different stores said they’d never seen something like it. They recommended treating like Black Algae, because it doesn’t brush off. They game me some Algaecide for Black Algae (at Leslie’s). It has copper and I’d prefer not to use it - they didn’t seem to really know what they were talking about.

I just bought a wire brush and was able to remove one big spot completely with a lot of brushing.

Other info that might help:
- my pool is really old (over 30 years) and apparently has never been replastered.
- I try to add 1gl of liquid chlorine and test in the following morning - all chlorine is gone. I tested CYA and it was about 90. At the store, they tested twice and it was about 30.
- My phosphate test says it’s low, their said it was super high.
- pH increased to almost 8.0 with no apparent reason. Never seen this in the past 3 years maintaining my pool. It’s always stayed at 7.2. Alcalinity is around 100.

I’m attaching photos that seem to represent the color very well.

I need help figuring out what to do here. Should I really add copper to my pool?
 

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IceShadow

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And no, don’t add the copper to your pool. So many threads here about copper stains that cause so many issues.
 

setsailsoon

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GU,

Ditto Zea1, don't add the copper! Also, you definitely need to SLAM. Please review the SLAM requirements in Pool School to the left. You have to do it all to be successful.

What else have you added for normal pool treatment. It's pretty normal for pH to rise due to aeration. If it did not rise in the past were you using trichlor tablets? What is the pH of your water you add? Can you please post a complete set of TF 100 test results?

Chris
 

duraleigh

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Apr 1, 2007
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I would hold on the SLAM for just a bit. Your description sounds like you have algae for sure but it is embedded in calcium deposits (or the plaster itself) and that is making it difficult to remove and will make your SLAM a failure.

First and foremost, stay out of the pool store. You have the best testing kit there is and you are about to get some use from it. The pool store will only confuse you, stay out.

1. Keep chlorine in your pool 24/7 about 5-10 ppm just as sort of a holding pattern so the algae doesn't get worse,

2, Get the green, hard to remove stains removed with that wire brush. This is gonna' take some elbow grease and a good attitude but, if it is calcium embedded algae, you have little choice.

3. You may not get ALL the staining eradicated but you certainly want to get most of it. Use some full strength bleach on a sponge to reduce the green after you use the wire brush.

4. Now that the stains are minimized, begin your SLAM.

I think there is a good chance the pool has been neglected for a prolonged period. It will take some effort but you can get it back There is also a fair chance that your plaster surface has deteriorated and algae is embedded in the pitting of the plaster. It will still likely clean up but you are fighting a tough battle trying to keep a clean pool when the plaster is destroyed.

So, did I mention to stay out of the pool store? All that junk they are telling you is peripheral and will not help you get your pool in shape. You need chlorine and determination.......that's it
 

GuRC

Member
May 1, 2017
12
San Jose CA
Thanks everyone for your insights. The first thing I tried here was the SLAM method. I set the pH to 7.2 and dumped 5 gallons of Chlorine in the pool. Next morning, I had an FC of 0.5 and CC of 0.5. I couldn't believe it! I also tried the cheaper testing method for Chlorine that comes with the TF-100 and it read 0 Chlorine. Where did it go? So, what I ended up doing was I spent hours brushing all the stains off. It literally took around 3 hours of agony and elbow grease. I hope I never have to do that again. Then I got nervous with the thing coming back and used the Dang algaecide. 3 days later, no signs of algae, but now I'll have to remove the copper from the pool. Oh well...

Algae problem solved, but I tried dumping another 5 gallons in the pool last night and had the same read this morning. I'll kick off another thread for the chlorine problem with more details. Thanks everyone.
 

GuRC

Member
May 1, 2017
12
San Jose CA
Hi there. Taking care of this pool for the past 3 years and recently (this past weekend) fought what appears to be a black algae problem successfully. Now I have a mystery that I don't even know where to start! Here's my TF-100 results:

FC: 0.5
CC: 0.5
Phosphates: ~150 (added Phos Free around 36 ago and pump is running - was ~250 before)
CYA: ~30-40
TA: 100
Copper: 0.2 (added algaecide this past weekend - I know how people feel about copper around here and I'll be trying to remove it in the next few days)
Temperature: ~80F (with solar blanket)
Pool is clean - water is clear and blue

Ok, so these are the reads as of this morning. What I didn't tell you is that I dumped 5 gallons of liquid Chlorine into the pool last night. This would usually bring up FC to around 14-15ppm in this pool. But it actually read 0.5ppm!! And to make things worse, this was not my first attempt. I did the same thing this past weekend (while fighting with the black algae) and had the same problem.

First thing that comes to mind is "expired" chlorine. Last night, 3 of the bottles were from Home Depot (have been using it for ~1 year without any problems), around 3 weeks old but stored appropriately, and the other 2 were from Leslie's (3 days old). The guy from Leslie's spoke very badly about the Home Depot ones (obviously) and guaranteed that his Chlorine was less than a week old, because they sell so much of it. So if bad chlorine is really the case here, I'd be extremely surprised. I've used chlorine from Home Depot before that was months old (stored appropriately) and it did bump up FC, although a little less effectively.

What other hypothesis do people have here? It's apparently not CC. Pool is clear. Maybe temperature? I've shocked the pool at this temperature before and never had problems.

Should I try powder? I'd like to avoid using tablets, to keep CYA down.
 

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setsailsoon

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GU.

OK no! Before we can help we need more information:
  • We need a full set of test results
  • Description and/or updated photo
  • Specifics on the Algae treatment including it's name and label information.
Once you do that an expert will advise.

Chris
 

setsailsoon

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PS If you added the one I think you did, you've also got ammonia to contend with. This will consume a LOT of FC until you remove the ammonia.
 

GuRC

Member
May 1, 2017
12
San Jose CA
New thread for the chlorine problem, containing the reads from this morning: No longer exists. Merged with this thread.
 
Last edited by a moderator:

Texas Splash

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What other hypothesis do people have here?
- It would help to know more about yoru pool and equipment. I would start by updating your signature so we can see what you have there
- How old is your TF-100 - specifically the FAS-DPD that you are using for the FC test? Has it been stored in a cool/dry place?
- For the algae, did you actually perform a SLAM Process to the point where you passed the required 3 criteria? One of those is the Overnight Chlorine Loss Test.
- Describe for us exactly how you are performing the FC test; just to valdate

 

Fast7

Well-known member
Aug 8, 2018
201
Plainfield, IL
GuRC,
Sorry to be blunt but NO, you never got rid of your algae in a first place.
You were under SLAM, couldn't hold chlorine and decided to dump in algaecide and call it a day.
It doesn't work that way, algaecide is designed to prevent outbreak, not to fix it.
Not only you never solved your first problem but you propably added bunch of FC eating amonnia and you start a new tread wondering why you can hold any FC.
Folow advice of a members here exactly if you want help to get thing resolved TFP style.
And please don't start a new treads on the same problem.
You will only waste people time working different possible scenarios without knowing background history.
 
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