Yellow Treat®


The Fast and Easy way to Kill Mustard Algae. Guaranteed.

  • Kills the toughest mustard algae fast
  • Requires less shocking
  • Safe for all types of pools

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Product Description

The Original Mustard Algae Killer

Yellow Treat® is the original mustard algae killer.  Introduced in 1981, Yellow Treat® has become the most trusted answer to yellow algae.

  • Kills Mustard Algae Fast: Yellow Treat®’s powerful formula kills mustard algae fast. In as little as 24 hours it will turn a yellow pool back to clean.
  • Less Shocking: Yellow Treat® requires less shocking to get the job done. This saves you time, money and hassle.
  • Safe for any pool: Yellow Treat® is tough on algae – not on surfaces. Meaning it’s safe for any type of pool. It also contains zero ingredients that stain. Keeping your pool looking beautiful after the algae is gone.

100% Performance Guaranteed

All our products are backed by a 100% Performance Guarantee. If this product doesn’t solve your problem we’ll fix it for free or you get a full refund.

Additional information

Weight 2 lbs
Dimensions 3.25 × 3.25 × 9.25 in
Product Type

Rescue Algicide


5 oz. bag, 2 pound bottle


5 oz. per 10,000 gallons

Surface Compatibility

All Surfaces

Sanitizer Compatibility

Chlorine, Salt and Bromine

Questions & Answers

  1. 0 votes
    A About 4 to 8 hours. Really it's when the chlorine comes down after shocking. If the chlorine reading is above 5 ppm you'll want to wait.
  2. 0 votes

    You could try adding more shock, but your best bet is to just stick with your regular amount of tabs in the floater. The reading should come back in a few days. You can also try using an OTO test and letting it sit for about 5 minutes, and just use the total chlorine reading as your free chlorine (there won't be any combined chlorine with the yellow treat).

  3. 0 votes

    Yellow Treat® will work independent of pH/CYA/FC/TC/etc. However, we do recommend you perform an additional shock after putting it in regardless of where your chlorine reading is currently. Hope that helps!

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Customer Reviews

2 reviews for Yellow Treat®

  1. Avatar


    Is it okay to use Calcium Hypochlorite with this product?

  2. Avatar

    Jim Guyton

    Yellow Treat completely removed mustard algae from my pool. However, I get a zero reading for chlorine, and I have added 5 pounds of shock chlorine.

    • Avatar

      Scott Hamilton

      This can happen depending on your type of chlorine. I would chlorinate as normal and use an OTO test for the chlorine (they are more accurate). I wouldn’t advise to continue to shock, since this can cause staining (and can be expensive). Although your test is giving you a zero reading – the pool shouldn’t develop algae (it’s more of a false reading). If the problem hasn’t subsided in a week, call us and we can diagnose why your pool is continuing to have this problem. Thanks!

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