Added way too much Black Alae Killer (Leslies)


New member
Jul 9, 2010
Well I screwed up and read the directions as per 1,000 gallons instead of 10,000 and well, yesterday I put 3/4 of a quart bottle of Leslies Black Algae Killer in my 10,000 gallon IG Saltwater Blue plaster pool. I am now looking at an extremely cloudy pool that foams and looks just downright nasty.

Hey and guess what The black algae is still on the stairs!! Suprise Suprise!

A couple of questions.

1) Is it safe to swim...
2) What do I need to do to:
A) Get rid of the foam
B) Eliminate the cloudiness.

Any help would be much appreciated as I am supposed to have the neighbors come over to swim tomorrow ( Which I think is not going to happen)

Thank you in advance!


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
I would shock the pool. I would not swim in it until it was cleared up.

Read "How to Shock your Pool" up in Pool School and the "ABC's of pool water chemistry"

Clorox will be the best item to shock your pool and it is the best way to get rid od algae. You don't need to spend the money on algaecides.


New member
Jul 9, 2010
Re: Added way too much Black Alae Killer Pool Testing Results

I just went out and tested my pool... NOT GOOD Vacation & A Newbie
As mentioned before I added way too much black Algae Killer in my pool when I got back from Vacation and just tested my pool...

FC = 0.5
Total Chlorine = 0.5
PH = 7.5
Alkalinity = 40ppm
CaC03 Hardness = 140ppm
CYA = 0

If I understand the directions:
16oz of bleach to raise Chlorine 1.5ppm 3 gallons to super chlorinate 25-30 ppm
RAISE PH from 7.5 to 7.8 (10 drops of reagent) = 2.5 lbs of Borax
Raise Alkalinity by 40ppm = 3.0 pounds of Baking Soda
Raise CaC03 Hardness 80ppm = 8 pounds of CaC03 chloride Dehi
CYA = ????? How much Cyronic acid????

Do you have any guidance as to when I should add each component, how long between testing etc...

Thanks in Advance!


TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
SWSuburban Chicago, IL
Correct me if I'm wrong but the active ingredient in the product you used contains copper - your copper levels could be very high right now - shocking could cause staining.

I'd confirm what was in the product you used and if it was indeed copper - get the copper level tested by Leslie's and post back here before you proceed with shocking the pool.