The million dollar question. Clarifier or flocculant??

This is a great topic to discuss because a lot of people do not understand the difference or don't do the process correctly for the way they decide to treat their water. Either choice is designed to help with cloudy water (dead algae, etc) and to clear it up. So let's get started so we can help you choose which is the best method to treat your water.

Clarifier is a great choice if you have time to wait or don't desire to drain out part of your pool. It is also reasonably effortless on your part. There is not much physical work with using this.

How it works is it takes all those small particles and joins them together (through a technical term coagulation) making bigger particles so the filter will catch them and pull them out of your water. The result will be a clear pool. If you don't need the results right away then I would go this route.

What I would recommend is to make sure you start with a clean filter because it will be causing a small pressure increase in your filter but all the stuff it's bringing into it. You also want to make sure all of the valves are open so you get full circulation. Then you want to evenly apply the dosage of your choosing to the surface of the pool and run the filter 24/7 until the pool is clear.


Flocculant is great if you want fast results! However, it does require some physical work and you will lose some of your water.

How this works is instead of making the cloudy debris larger to get caught in the filter this simply makes all the particles sink to the floor. From there, you vacuum the pool to waste and remove all the debris. You should have clear water from there.

If you have a cartridge filter I would go ahead and remove the cartridge before you apply the floc. If you have a sand or DE filter then move the valve to "recirculate". This will essentially bypass the filter so the floc doesn't go into the filter. Once that is done go ahead and apply the floc evenly across the surface and allow the system to run for 2 hours. Once that is done turn off the system and make sure it won't turn back on (even turn off the breakers for good measure). Then you want the water to sit still for 24-48 hours to allow everything to sink. Usually you can treat in the evening and the next morning get started with vacuuming. Vacuum slowly. We don't want to cloudy stuff on the bottom to be disturbed. TIP: Check the weather. If it's set to rain during the treatment postpone it. The rain hitting the water would be enough to disturb the process.


If you have any questions or want help please don't hesitate to reach out. Let us help you choose what's best!

8 Responses

  1. Linda
    Chlorine King, My husband is trying to use floc to clean out our pool. We let it sit over the winter and it got pretty bad but the upside it is looking alot better. The floc doesn't seem to be working as you can see a bunch of chunks floating around. Are we doing something wrong? Linda
    • Great question Linda. Lets see if I can help. There's not a lot of information in your post so I can try to work up some scenarios you could possibly be experiencing. First things first, floc is excellent if you're trying to get a pool clear quickly for a weekend party and such. Here are a few issues you could experience with floc. 1) Did you let the water circulate for a few hours after applying it? If you don't let it circulate this could inhibit it's effectiveness. 2) How long did you let the floc sit with the system turned off? Each brand is a little different but I try to let the water sit for a day at least or two if I can. 3) What area do you live in? If you're here in Pinellas County we recently had a few days of rain. Rain water, or anything that disturbs the water, will stir up the floc. It's a very "sensitive" procedure that you have to be very slow and consistent with your movements in the water, even when vacuuming, because you can stir it all back up if you're not careful. Those are just a few situations where floc can give you some problems. Good luck!
  2. Anything that could get rid of stains and algaes are a welcome for me. I really do not want to see the grotesque, slimy thing clinging to the sides of my pool. I always want my pool to look sparkling blue, clean and inviting. If this is what it takes for me to have an uncloudy pool then, I'd like to try it.
    • Hey Cherry, If your pool is cloudy either one of these options will help. However, floc (except for aluminum sulfate) will not work on live algae so the first thing you'd need to do is kill the algae if there's algae in the water. Then you can proceed with the floc treatment. If there's very little cloudiness to the pool then clarifier will more than likely be the better option. Just make sure you clean your filter before and after the application. I hope that helps!
  3. Please help!! I’ve been killing a infestation algae pool since Thursday! I’ve got it all dead and nothing but dust on the bottom of the pool. I can’t seem to pick it up with my vacuum. I’ve have gone through 4 fiber filters and I am about to give it!! Please help!! I don’t know what else to do to collect this algae dust! Cassie!
    • Hey Cassie! Thanks for the question. For some reason I just got alerted of this question. Do you have a waste line/DE/Sand Filter? If so you can vac to waste and remove that stuff from your pool. I hope this helps!
  4. I have a large free form In ground pool that had major leaves on the floor I have scooped it all up but the pool is a dark green monster The filter will not run efficiently and effectively because too much algae Can I run it on recirculate after I add the shock Will it have the same effect? Thanks for ur time and help I’m having a large graduation party in 3 weeks please help I’m about to drain this HULK
    • Hey Tom! Yes, run the filter in recirculate as you annihilate the algae with chlorine for the first 24 hours. Wait to put it in filter mode (after you backwash) until you see the pool turn a cloudy blue. That will ensure all of the algae is dead. Here is a video I did showing exactly what to do. You do not need to drain the pool if it's only algae left in the pool. <a href="" target="_blank" rel="noopener nofollow ugc">Green Pool Clean Up</a>

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