ARGH!! ??pool algea??

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
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ARGH!! ??pool algea??

Postby cfamily » Mon 21 Jul, 2008 20:17

I have been seeing yellow 'slime' on the floor of my above ground pool and up the walls now too...stores told me yellow/mustard algea ... doesnt seem what they have given me to try it just keeps coming back!!..water is clear as day...there is no bad smell..just yellow stuff...can brush it up and it clouds and dissapears in the water then I guess it resettles...I have a DE filter also have cleaned that out too....HELP ANYONE....have had my pool for 8years and this made its first ugly appearance at the end of last season and it made its appearance this season about a week ago...I am in Massachusetts....... :(


Postby Guest » Fri 25 Jul, 2008 16:54

As a Ma. native I'll see if I can help.

Without knowing pool type, size and chemical balances it's tough to give specific help.

In general, if this is mustard/yellow algae you need to shock the pool and hold that high level to kill it. How high depends on many factors, cyanuric acid level being #1.

If you can't test your pool yourself you have to rely on the pool store. Most pool stores will sell you lots of chemicals when all you really need (assuming chemicals balance is good) is liquid chlorine.

Yellow algae can be tough but with a proper chemical balance you can kill it and keep it away.

If you are able to post chemical levels (free chlorine, total chlorine, pH, TA, calcium hardness and cyanuric acid levels) along with pool type and size I can give you better advice.

Good luck with it.


Postby LuvtheSun2 » Wed 20 Aug, 2008 11:11

I have also been battling something since the middle of last season. About 2 weeks ago I was informed that I had high phospates and used a chemical called "Revive". Well it got rid of the phosphates however the stuff that looked like sand has multiplied and is growing and now all over the bottom of pool looks like numerous brown/yellow clumps of junk. Chlorine will not touch this stuff, I have vacuumed to waste and it still keeps growing. Finally found a pool store that informed me that I may possibly have "mustard algae". I am in the process of following the steps: First, you have to use power flock to weight this stuff and vacuum to waste, the next step will be to use Yellow Out followed by a lot of shocking. I will keep you posted to let you know if all this works with pool. So far, nothing has worked and it has been very frustrating. Research mustard algae and contact a pool store that is up to date on this type of algae without going through the process of just keep shocking. Mustard algae is resistent to chlorine.

Yellow mustard algae

Postby Dadof3 » Thu 21 Aug, 2008 15:18

I went through same problem last year. PH was perfect, Chlorine was perfect, did shock after shock, left cover on for 5 days and pool was still green!! I ended up draining and closing pool for the year. This year has been great up until last week. Pool turned green again!! I talked to my father-in-law and was told there was a product that looked like black tar, and within a day of pouring this in his pool, it was clear again. Problem is , that was 15 years ago and he can't remember what it is called. Does this sound familiar to anyone?? Is "Yellow Out" like black tar?

ARGH!! ??pool algea??

Postby Beecleanpools » Tue 22 Oct, 2013 00:49

I bet money you have a phosphate problem. If you have high phosphates the chlorine will skip the algae and try to fight the phosphates. Expect phosphates to be raised overtime or by dust storms, rain, flowers, and leaves. Ask your pool store for them to test for phosphates. And stop wasting your money on shock.
Water chemistry is science. When you go to the pool store ask them to test for everything, including phosphates calcium and cyanuric acid. Do not take advice from people that are not a certified pool technician. They destroy everything. Do not add anything with out testing for it first, Ray Charles and Stevie Wonder can see this is a bad idea.
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ARGH!! ??pool algea??

Postby chem geek » Wed 23 Oct, 2013 00:49

Do you realize that the last post in this thread was in 2008 making this thread 5 years old?

What you wrote about chlorine and phosphate is pure baloney and not science at all. Chlorine and phosphate do NOT react with each other. Where do you get such inaccurate information?

Phosphates as well as nitrates are essential nutrients for algae growth. If the Free Chlorine (FC) level is lower than around 7.5% of the Cyanuric Acid (CYA) level, then green or black algae can grow faster than chlorine can kill it and conversely if you maintain the FC/CYA ratio at or above his level than chlorine are killed faster than algae can grow even if there are as many phosphates and nitrates as the algae could possibly use. Algae growth is ultimately limited by sunlight and temperature. I've had over 3000 ppb phosphates in my pool yet kept algae from growing using chlorine alone and there are people with 5000 ppb and even one with tens of thousands of ppb phosphate that do not have algae growing due to proper FC/CYA levels.

So phosphate removers should be seen in the same vein as algaecides. They are not necessary to prevent algae growth as chlorine alone at the proper FC/CYA ratio is sufficient for that purpose, but it is insurance if you believe you are unable or unwilling to maintain the proper chlorine level. The use of Trichlor tabs, for example, increases the CYA level over time so if you don't proportionately raise the FC level as the CYA level rises, then algae can grow. The following are chemical facts independent of concentration of product or of pool size:

For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

What do you mean by a "certified pool technician"? Is that where you are getting your misinformation? Is this link your website? Is your Certified Pool Technician training from Aquatic Training Institute which is an online course?

If you want more accurate training, I suggest you become a Certified Pool Operator (CPO) and then look at this link for additional information. Your advice about testing first before dosing is sound, but pool stores often test inaccurately. One should get their own good test kit, either the Taylor K-2006 or the TFTestkits TF-100 with the latter having more of the reagents that are used the most. For additional information on how a residential pool owner can properly manage their own pool, read the Pool School.
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ARGH!! ??pool algea??

Postby Jackson1 » Mon 24 Mar, 2014 15:40

I always thought a little algae in a pool is a good sign. However, yellow slime sounds disgusting. I hope everything worked out well for you.
Hey, does anyone know about the service that this company - Ameraguard provides? (Spray-on coating?) I want to get it for my truck bed and boat, but would like to hear any and all experiences with it. Thanks!

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