I have had my pool for 27 years and this is the first time I have had this problem. I have a brown algae that looks like a stain in the deep end of the pool. It started on one side and had worked it's way around to the other side. There are also spots in the shallow end. I have talked with local pool stores and I get a blank look when I describe the problem. One shop told me it was algae in the dirt on the outside of the pool and was coming through the vinyl. I have a salt water pool and maintain my chemicals weekly. I mostly use the local pool store to do the testing because the do a lot more of it that I do and I am also somewhat color blind. Last week I poured three (2) gallons of liquid chlorine in the pool and the algae (Stain) was almost completely gone. Today I opened the pool and the algae (stain) was back in force. I poured 3 gallons of chlorine and 2 bags of shock and the algae seems to be gone. I am doubtful that I have fixed the problem and expect the algae to return in a couple of days. One of the pool stores suggested AquaFinesse Pool 170 gr tablets. A pail of 8 tablets is about $50.00. I don't mind spending the money but had anyone else seen this problem and is this the solution?
Brown Algae that will not brush off
- Thread starter jalles
- Start date
Hi there and welcome to TFP 
glad you found us.
You'll be hard pressed to have anyone here reccomend any pool store potion. We do advocate and gladly help teach taking over your own testing and pool treatment. It is very satisfying to the wallet not to mention knowing exactly what to feed the pool for solving various issues. Such as bleach for needed chlorine. Muratic acid to lower PH, baking soda to raise total alkalinity......etc.
And, as often as the pool store does testing, thread after thread year over year here attests to their inconsistency and therefore often inaccurate numbers, particularly on the CYA measurement.
With that being said, I'd try 2 things....a chlorine puck, like trichlor held on the stain for a minute or so causing it to fade would indicate it is organic (as your chlorine use seemed to indicate fading). On the other hand if it were metal stain (unlikely I'd think on vinyl) a vitamine C tablet held on it should fade it.
Knowing what kind of stain for sure will provide the roadmap for the cure.
glad you found us.You'll be hard pressed to have anyone here reccomend any pool store potion. We do advocate and gladly help teach taking over your own testing and pool treatment. It is very satisfying to the wallet not to mention knowing exactly what to feed the pool for solving various issues. Such as bleach for needed chlorine. Muratic acid to lower PH, baking soda to raise total alkalinity......etc.
And, as often as the pool store does testing, thread after thread year over year here attests to their inconsistency and therefore often inaccurate numbers, particularly on the CYA measurement.
With that being said, I'd try 2 things....a chlorine puck, like trichlor held on the stain for a minute or so causing it to fade would indicate it is organic (as your chlorine use seemed to indicate fading). On the other hand if it were metal stain (unlikely I'd think on vinyl) a vitamine C tablet held on it should fade it.
Knowing what kind of stain for sure will provide the roadmap for the cure.
I don't know if you read my note completely, when I added the liquid chlorine the (Stain) disappeared , as in completely gone. Problem is the algae comes back.
I did read it. Sorry....somewhere I thought I saw "staining". The cure for algae is to follow what we call the SLAM process
Shock
Level
And
Maintain
Pool School - SLAM - Shock Level And Maintain
But you definitely need to be able to accurately test your FC with an FAS-DPD chlorine test to follow that process.
And while that is the cure, not enough chlorine for your CYA level (Pool School - Chlorine / CYA Chart ) is the cause.
Sorry for the confusion. It looks like a stain because it does not brush off. It is not slimy and has no physical attributes other than the color. The water is crystal clear. I have a problem with test kits because I am somewhat color blind and colors that are close all look the same. I have used the same pool store for all 27 years and the current manager has been there about 15 years. I have not asked for printouts of my chemistry recently but I will on Monday. After all of the chlorine and shock there is no algae residue at the bottom of the pool in the morning. I am pretty anal about stuff in the pool and I skim daily or more and I vacuum 2 to 3 time per week. I have a barracuda 3 vac that I use and it works great. Today is Sat, and when I opened the pool this AM about 1/2 of the discoloration had returned.
Is there a test kit that does not require comparing colors?
I am familiar with algae and when I have a growth there is a residue in the bottom after shocking. I am not getting that with this problem. It goes away with large amounts of chlorine but comes back with no residue to vacuum up.
Is there a test kit that does not require comparing colors?
I am familiar with algae and when I have a growth there is a residue in the bottom after shocking. I am not getting that with this problem. It goes away with large amounts of chlorine but comes back with no residue to vacuum up.