Clarifying the Flack on Flocculants & Clarifiers

Perhaps the most overused chemicals in the now vast array of pool chemicals, clarifiers and flocculants are often thought to be the “wonder chems” that will turn your water crystal clear in an instant. Let’s take a closer look as to when a clarifier is called for and in what circumstances a flocculant should be used as both have specific applications for various situations. First and foremost before adding any chemicals to your pool test your water to make sure water is balanced and check your filter system making sure it is not in need of backwashing, the baskets are clean etc. If one or both of these are not in optimum order your water will be cloudy and should be corrected first.

Sometimes, however, chemically the water is balanced and everything seems perfect and your water appears clear but then you switch the pool light on and whoa! It looks like fog city in your pool. This is when a clarifier or flocculent may be applied. Flocculants and clarifiers are designed to enlarge the smaller particles of dirt and debris that your filter system can’t pick up. Filters are wonderful at straining out large particles but each media has its own limitations for ex. DE filters are said to pick up particles 2-4 microns in size with a Cartridge 15-20 microns and Sand coming in last at 25 microns and higher and as the filter gets dirtier with a higher pressure it becomes less efficient. If you can imagine the human hair is about the size of 17 microns, but particles as innocuous as dirt to those which can be more harmful to swimmers such as Crypto, E-Coli, and Giarda may be too small for your filter to pick up.

The desire of using flocculants and clarifiers is to make these unwanted particles larger. Chemically, dirt particles are negatively charged and repel each other, by adding clarifier or flocculant (polymers which are positively charged) the dirt and debris will attract to the polymer and form a larger structure. In the case of a clarifier these can now be picked or strained out by your filter system and your water becomes clear. You the pool owner can backwash these particles easily from the filter or wash off a cartridge. In the case of flocculant use there is a different application. I would urge users to follow the label instructions carefully and fully. As an example, the flocculant I carry in our store is designed to force particles to bind together and fall to the floor of the pool. The application is to add the flocculant and filter the pool for one hour then shut everything down allowing time for the suspended particles to go to the pool floor and vacuum the next day very slowly to waste. You may need to vacuum more than once with flocculant and if you can not vacuum to waste you may clog the filter where you will have to backwash or hose down the filter a couple times.

I myself, have never been a huge proponent of Flocculants, mostly because they tend to clog up your filter systems unless you are able to vacuum to waste and in my area wells are so prevalent which means to properly use the Flocculant you most likely will be adding water to the pool which can cause other chemistry problems such as staining and metals in the pool so I advise customers to stick with the Clarifiers. My preference and opinion only. As always folks, remember the more chemicals you add to your pool increases TDS (Total Dissolved Solids) which down the line can create problems with your water chemistry. My motto has always been to add what is needed no more, run your filter system the correct amount of hours and take the time to keep the area around the pool clear and clean which will help with debris falling into the pool. Keep it safe!!!! Don’t forget to write in your questions.