Hello -- I think I have mustard algae.

Hello,

First post on this forum or any pool forum. I have an above ground 10,000 gallon (est) pool that uses a DE filter and a 1.5 HP pump. Just opened the pool for the first time after buying a new home and things went smooth. Have one issue and not sure how to get it solved, so I am hoping everyone here has some ideas. Good to meet you all.

~Ross

Hi, Ross, and welcome to the Pool Forum! How can we help you?

. . . membership updated.

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Thanks guys. Yea I have been using the search and Google for a lot of little things. My biggest issue I think is mustard algae? I say I think because of the color but when I broom it, it disapates into the water. After some time it returns. From what I read the best way is algecide and shock since it's pretty resistant to just chlorine.

One major search thing I found and did not know is to point the jet down and not up. Seems like that solves many pool clarify issues.

Love to hear your thoughts on my algae issue.

Clarification: "shock" is just regular chlorine. "Shocking" just means 'adding more chlorine than usual!'

Mustard algae tends to be very chlorine resistant, and tends to reoccur. Most algaecides are ineffective against it. There are several options, but most have undesirable side effects.

1. Very high levels of chlorine, typically 30 - 50% of your stabilizer level. (If your stabilizer level is 60 ppm, you'd probably need 20 ppm to get rid of mustard.)

Contrary to what many think, you CAN swim with chlorine this high, but it is hard on swimsuits and may dry your skin.


2. Heavy duty application of high concentration copper algaecide.

The problem with copper is green, greenish-blue, or bluish-green: copper stains pools and hair.


3. Monochloramine, produced in your pool by raising the pH, adding products like Yellow OUT, and then 'shocking' the pool.

But monochloramine is VERY irritating to people, and is somewhat hard to remove.


4. High levels of chlorine (15% of your CYA level) + low levels of phosphate (< PO4)

Currently, this is the option I'm testing locally and am most hopeful about. You do have to use another testkit, and you have something else to buy, but the cost has been lower than I expected and the result -- so far -- has been better. This is the only option that has no bad side effects on pool users.

No matter which way you go, you need to manage your pool chemistry accurately, which is why we recommend the Taylor K2006 kit. See http://pool9.net/tk/

If you want to go with the low phosphate option, you'll ALSO need the phosphate kit, shown on that page. With a 10K gallon pool, a single quart of this product should be enough:

Clorox Phosphate Remover

The Kem-Tek product we'd been recommending is being phased out, and replaced by the Clorox line. But for now, shipping times will be slower.

Get 2 quarts, if you want to maintain low phosphates all summer. And keep in mind, low phosphates do NOT kill algae; it simple makes the algae slower growing, and more susceptible to chlorine.

Oh wow your awesome for sending me this information. So I assume with what you said you agree that it is mustard algae based on the color and the dissipation factor?

Right now I am using Aquachek Pool & Spa Test Strips: Free Chlorine. It does check for Free Chlorine, pH, Total Alkalinity, and Cyanuric Acid (stabilizer). Today in NJ we had a hot day so my chlorine went from perfect to fail, as well as the pH. I guess that could have added to the mustard algae issue. I would have thought with a DE filter it would pick it up? Although the skimmer is at the top and I have nothing at the bottom of the pool. I did point the jet down in hopes of getting the algae to the surface and for the DE to pick it up.

Also thanks for correcting me on the shock and chlorine, I mis-spoke but meant what you said. I think I might go that route, shock, if you can confirm that what I describe is mustard algae.

Thank you again!!

We call test strips 'guess strips' for a reason. Get the kit Ben linked above. You need it.

Will do! Figured that something cheap would be a guess.

Anyone order from these guys: http://www.vminnovations.com ?

Yes, they are one of the sellers on Amazon. VMI and Amato are the 2 most common. There've been a few complaints about both, with Amato doing a bit better than VMI, but as far as I can tell, they'll both make things right eventually.

For a while, Amazon was selling the K2006C directly, and that was preferable, but currently both the K2006a and the K2006c seem to be available only through 3rd parties.