Do I Have Brown Dirt Or Is It Brown Algae?

by Donna
(TN)

I keep getting what looks like real fine brown dirt that settles on the bottle of my pool.


I spent several hours vaccuming just the shallow end yesterday only to fine the same brown mess this morning.

I had even cleaned my cartridge filter immediately after vacuuming. It appears that as soon as I take the vacuum system out, it shoots everything I just sucked out back into the pool.

This isn't the first time.

It has already happened several times since early April.

My builder said it sounded like pollen.

I don't think so.

Today, I had a guy at Leslie's Pool supply tell me it was brown algae and to use a copper based algaecide.




Thanks for the question Donna

Your problem could be dirt, so before we start adding all kinds of chemicals, let's take a look at what you do and your filtration system.

The question says you have a cartridge filter, which I highly recommend. Let's say your cartridges are fairly new, without any tears or rips, and you keep them cleaned out. Once per month for normal usage is good.

The skimmers are kept clean and you clean the pump basket as well.

All the chemical readings are good. You keep your chlorine level between 1.5 - 3.5ppm.

The question does say that after you vacuum the "dirt" comes right back into the pool. This could be a torn or ripped pleat on the cartridge.

But, if the pool looks good, and after a while, maybe overnight, the brown dirt reappears in the same spot, then you probably have brown algae.

Now the pool guy said to use a copper algaecide, probably chelated copper. One of the big concerns for this kind of algaecide is that it sometimes produces what's called "pool goo" or "pool tar" in vinyl swimming pools.

I answered this question here:

Sticky Pool Algaecide On Vinyl Liner

Unfortunately, your pool guy may have been mistaken. Any algaecide, regardless of its use, is for preventative maintenance, not to get rid of existing algae.

It's an insurance policy, nothing else.

The only way to get rid of algae, whether it's brown, green, or whatever, is to give your pool a good chlorine shock and a little manual labor.

Brown Algae

If you keep your pool chemicals perfect, but still have a brown algae problem, I would recommend a PolyQuat 60 algaecide. This doesn't have any metals and will work for your issue.

After you add PolyQuat, you free chlorine level will drop. You'll need to add chlorine a day or two after.

Remember to test once, if not twice, per week during the Summer for all your chemicals.

I recommend using a Taylor FAS-DPD K-2006 pool test kit. The best on the market and the one most pool professional use.

Water Testing Kit

Pool Water Testing

Hope this clears it up for you. Have a great and safe swimming season.

Robert

Comments for Do I Have Brown Dirt Or Is It Brown Algae?

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Aug 06, 2012
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Gray flaky stuff on surface of pool
by: Reggie

Hey,

I have researched and not seen an answer to what this is. I have fine med gray flakes floating on the surface of my in-ground pool water. I can scrap them out with the net. This summer the pool was chipped out and a new pebble tech liner was installed, new tile and a completely new pump system without sand. So basically everything but digging the hole again and the jets were done. Yes even have a new light. I live in Phoenix, so hot and dry. And now I have this junk. Please help.

Thx so much
Reggie

Aug 06, 2012
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starstarstarstarstar
Gray flaky stuff on surface of pool
by: Reggie

Hey,

I have researched and not seen an answer to what this is. I have fine med gray flakes floating on the surface of my in-ground pool water. I can scrap them out with the net. This summer the pool was chipped out and a new pebble tech liner was installed, new tile and a completely new pump system without sand. So basically everything but digging the hole again and the jets were done. Yes even have a new light. I live in Phoenix, so hot and dry. And now I have this junk. Please help.

Thx so much
Reggie

Dec 18, 2014
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First You Say No Then You Say Use Algaecide??
by: Greg

One minute you say algaecide are only a preventative not a cure and then you recommend a algaecide to fix the brown algae.?????????????




Thanks for the comment Greg but I'd like to know where I said that using an algaecide will "fix" a brown algae issue. If you could please refer to that it would be much appreciated.

We need to define our terms and make ourselves clear. Every pool has algae, bacteria, organic matter, etc... We must add enough chlorine to kill these organics faster than they reproduce.

Chlorine has a kill rate of about 2 - 3 seconds where, to the best of my understanding, algaecides have a much slower kill rate. This is why simply using an algaecide a pool owner will not be able to kill algae faster than it can reproduce.

By supplementing the chlorine with a PolyQuat 60 it helps increase the kill rate in the event that the CL level is allowed to go low enough to be unable to kill quickly.

In this event a PolyQuat 60 algaecide would be recommended.

Sep 04, 2015
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Filtering Brown Dead Algae
by: James

32 ft dia rd above ground,vinyl liner, approx. 17000 gal, 300lbs # 20 sand Hayward filter Chemicals in range. Get a steady crop of brown dead algae, lightly over bottom, more in seams every 3-4 days. Very fine powder like.

Brushing to make it disappear back into water is easy but sand filter is very poor at removing it. Electric Robot fine cloth filter is fair. Most effective is vac to waste but lose 800 gal water. Is there a coagulant that would make the fine brown algae more filterable? Am I missing something?

May 05, 2016
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I Think it is a brown algae
by: steps

Brown algae is also known as mustard algae. They can often be confused with dirt or sand. Direct chlorine treatment will not work. Algaes have very strong layers which is difficult for the chlorine to penetrate into the algae. It is recommended that you first brush off the algae using a stiff steel brush, this will expose the not so strong under coverings of the algaes. Then you pour chlorine into those algaes. Wait for a few days once when the pool is algae free shock the pool by adding granulated chlorine and then some amount of algaecide 60. See whether that helps. If it does not work out try calling for professional help.

Jul 14, 2016
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Brown Algae Inground Pool
by: Michael

I have an 18000 gal in ground liner pool. I keep getting that fine brown algae every so often. I am on time with my chemicals each week. One week I shock, and the next I use pristine blue, a non chorlrine algaecide. After a few days of using the chemical or shocking, this fine brown algae reappears? What can I do to remedy this??




Hi Michael. I'll need a full list of your chem numbers: FC, pH, TA, CH, and CYA. I also need your filter kind and pool size. Pristine Blue is copper which you should never use due to several important reasons.

Get back with the numbers and we'll go from there.

Robert

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