Opening a Green Pool - Same Idea as a Clean Pool?


Well-known member
Sep 9, 2017
Nashville, TN
Confession time. After two weeks of rigorous brushing, vacuuming and SLAMming - I flocced using Leslie’s alum. I know I broke the cardinal rule. Please forgive me. On the upside I can now see what the heck was going on in there. I appreciate everyone’s guidance. I think I probably could’ve reached this without flocking but it would have been another two weeks before the white, suspended fine particles would have eventually been caught by the sand filter. Maybe less if I added DE.
Will work on a formal OCLT this weekend. Next step is figuring out why the gas heater won’t ignite. If it’s not an easy fix I’ll call in a professional because I don’t want to blow up the neighborhood.
Here’s some before and after to give some inspiration.


Mod Squad
LifeTime Supporter
Jul 10, 2012
Tallahassee, FL
Jason, Do you have a pic of right before you put that BAD floc in?? Guess it is not that bad if it helps like this.

Everyone needs to know you CANNOT use floc of any kind unless you can vacuum to waste in some way. If you send floc through your filter you risk clogging it up so bad it will have to be taken apart and stuff replaced like sand or grids.



Well-known member
Sep 9, 2017
Nashville, TN
Kim makes a good point. So for any curious pool owner who finds this thread some day in the future.... You can't just toss in the flock and cross your fingers. You really need to have patience and plan. Here's how it's working out for me.
Late Wednesday Afternoon - Made a slurry with the Alum in a bucket. Stirred it up with a big piece of PVC pipe. Stirred. Stirred. Stirred a little bit more. Set valve to recirculate. Removed skimmer basket. Then I cast/splashed the slurry mix evenly around the pool. Let the pump run for two hours. Then cut it off and went to bed.

Early Thursday Morning - Woke up and was stunned by the increase in clarity. You can see the Alum "goo" on the bottom, it looks almost like a reflection of the clouds.

Late Thursday Evening - Got home late from work. It was nearly dark. The layer of Alum goo had increased significantly. I hooked up the vacuum, turned off suction from my main drain so only the skimmer (where my vac hooks up) was sucking, set valve to waste, <--VERY IMPORTANT, turned on the water hose so I could offset the water loss from vacuuming to waste, and finally kicked on the pump. Vacuuming the goo feels almost like you're vacuuming up fog or a cloud. If you go too fast, or if you're too aggressive with your movements you'll stir up the cloud. It took me about three cycles of vacuuming until water levels dropped to near the bottom of the skimmer then stopping to let water levels rise, repeat. Here's how it looked when I was finished.

Friday - I decided to let the water sit still today just in case there was still some floc in the water column that needed to drop. I'll vac again this evening, add a sock to the skimmer basket and keep an eye on this while filtering and back washing as needed.

Sorry for the crummy picture quality. My phone's primary camera is broken so I have to take everything with the selfie camera!
All said and done, I think over the past two weeks I've added 14 jugs of 128 .oz 10% bleach. The first few days, I went through chlorine like candy.... The next several days were down to about a jug a day.... And this past week has been about half a jug a day. I assume I would've needed at least another two weeks and 8 more jugs to get to the finish line.

So... While Alum is not for everyone and is essentially treating the symptoms not the cause... I think with patience and research, it can be a helpful tool to be aware of.