Need to understand what happened after adding Algaecide 20%


New member
Sep 4, 2007
I just recently added about 20 onz of Algaecide 20% from AquaChem that I bought at Walmart just because I noticed some small black dots on the bottom and other areas of the pool. I thought it was algae because when I brushed some of them easily and others would not come out. I noticed that after adding the Algaecide, brushing and running the filter for several hours it improved with feower spots were left.

What I'm concerned about is that whenever the pump is running there are bubbles forming at the waterfall area and there is a weird strong smell (4th day after adding Algaecide). How can I know if it's safe to get in and how do I get rid of the bubbles and smell and get it back to normal.

I only have the simple AquaChem test kit for Chlorine and Ph. There are no stores here that test pool waters and there are limited test kits available.

I'm a nebbie with a 14,000 gallon SAG pool, 2hyp, 48K DE filter. Filter pressure is close to 20 not too high for a Backwash but if netted I can do the BW and release some of the water with Algaecide. Since I installed the SWG I only add salt and Muratic Acid when needed. Ph levels have been fairly easy to control with adding about 8onz of Muratic acid once a week.

Weather has been variable lately (rainy and then sunny).

Please help! Let me know if I need to post more info about the pool.




TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Yea, it is best to avoid that kind of algaecide. It should take about a week from when it was added for it to dissipate, assuming you maintain proper chlorine levels.

Maintaining proper chlorine levels is crucial. Do that and you won't get algae even without algaecide.