Leslie's yellow out- tried and don't like it

Apr 14, 2013
74
Thought I'ld provide a report on my experience with yellow out. I tried it as I thought I had mustard algae and super shock was not removing it. Yellowout was easy to apply and wiped out any visible algae very very quickly. HOWEVER, it has a nasty side effect. FC drops for many many days after, I'm about 10 days out and still seeing a drop of FC between 2 and 3.0/night. Not nice. So trying raising CYA from 30 with some liquid conditioner. Hopefully that'll raise the cya to about 40 and slow down the FC loss
 
Notri4MeBikeSwim said:
Thought I'ld provide a report on my experience with yellow out. I tried it as I thought I had mustard algae and super shock was not removing it. Yellowout was easy to apply and wiped out any visible algae very very quickly. HOWEVER, it has a nasty side effect. FC drops for many many days after, I'm about 10 days out and still seeing a drop of FC between 2 and 3.0/night. Not nice. So trying raising CYA from 30 with some liquid conditioner. Hopefully that'll raise the cya to about 40 and slow down the FC loss
That overnight loss could also be that you didn't completely kill the algae. Maybe you just stunned it, and once it has a chance to recover, you'll be no better off than you were. Not all algae is visible to the naked eye. A bloom begins with increased chlorine demand, then the water goes hazy, then cloudy, and then green. It takes a few days, generally, for it to go from beginning to visible, and, like unwanted weight, it's faster to grow it than to get rid of it.

That kind of overnight loss is a definite sign that you need the SLAM process in your pool.
 
Popular subject recently. The yellow out actually tries to use ammonia to kill the algae ... and removing the ammonia takes a lot of FC. We do not recommend any of these so called quick fixes. The slam process works just fine every time.
 
There are many different yellow/mustard algaecide products with "yellow" in the name. This one being sold by Leslie's is Coral Seas Yellow Out and is 100% EDTA. Though EDTA is sometimes used as a metal sequestrant, it is also an algaecide, but EDTA breaks down from chlorine somewhat quickly which is one of the reasons we recommend HEDP-based metal sequestrants since they are not only more effective, but are more resistant to breakdown from chlorine (they still break down, but more slowly).

So in this case, the overnight loss may be due to chlorine oxidizing the EDTA. Unfortunately, there is no way to easily distinguish the chlorine demand from breaking down a chemical vs. getting rid of algae. This is yet another reason why we avoid using these kinds of algaecide products (EDTA, sodium bromide, ammonium chloride, etc.) since they are not only extra cost and generally not needed, but they muck up techniques such as the Overnight Chlorine Loss Test (OCLT).

Please let us know if the algae comes back after your chlorine demand returns to normal. If it does, then that means the algae is hanging out in places where it will get reintroduced such as behind light niches or under removable ladders or in poles and other equipment you use to clean/brush the pool.
 
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