Getting Clear Pool Water with a Sand Filter
There are three types of pool filters available on the market today: DE (diatomaceous earth), sand and cartridge filters; each comes with its pros and cons.
When rating in terms of performance, DE filter is the best, followed closely by sand and cartridge filters in that order. Sand filters are the most popular pool filters, however, due to their pocket-friendly price and high performance in larger and busy commercial pools.
Sand filters use 20 silica filter sand that can filter down to 20 microns, meaning any debris smaller than 20 microns will pass into your pool or spa water, making your water cloudy even though all your pool chemical levels are right, including free chlorine levels.
DE filters use filtering media that can filter down to 1–5 microns, and you can imagine how huge the difference is.
If you have a sand filter, a good thing is that you can improve your water clarity by using a DE media + filter aid in the skimmer. Note: You cannot mix any DE filter media with sand or use them in the sand filter tank to replace filter sand—you can only use it in the skimmer.
I prefer using the special DE media + filter aid because it can filter down to 1 micron, while the normal DE filter media can filter down to 5 microns. This means that you can still use DE media + filter aid to improve water clarity in your pool if you use the normal DE filter media that can filter down to 5 micron.
Another added advantage of the DE media + filter aid is that, despite making your water sparkling clear, it also prevent metal stains in pools by filtering out all heavy metals—including copper, iron, silver, and magnesium, which are common when using well or borehole water in your pool or spa.
However, if you have or prefer the normal DE filter media, you can still use it in the skimmer to improve your water quality and clarity, since it will filter and trap smaller particles 20 silica sand cannot trap.
Remember, all these should not be a shortcut to back-washing your sand filter, or a scapegoat to replacing your filter sand after every three to five years, but to only improve efficiency of your sand filter, being that it can only filter down to 20 microns.
Alternatively, most pool owners use different filter sand alternatives that can filter down to smaller than 20 microns to completely replace filter sand, boosting water clarity, reducing backwash times, and increasing the lifespan of a sand filters.
This article shows you how you can use a DE filtering agent in the skimmer to boost the efficiency of your sand filter, compares other sand alternative filtering agents that can be used to completely replace filter sand, and which is better to use between DE media and sand alternatives.
How to Use DE Filter Media in the Skimmer to Improve Sand Filter Efficiency
- Turn on the filter while the pump is running, and note the pressure reading before doing anything.
- Mix 1/4 cut of DE with water in a bucket, and then pour it slowly into the skimmer. Ensure that you remove any skimmer shock if available before adding the DE agent.
- Leave for about 2 minutes.
- Note the pressure on the filter again. If the pressure has not gone up by 1 PSI, repeat the second and third step until it does. This will take approximately 1–2 cups of DE.
Note: Since the efficiency of the filter is improved and it may thus catch many fine particles, it is important to watch for any changes in pressure.
Which Is the Best Filter Sand Alternative to Use in My Sand Filter?
The most common types of filter sand alternatives with higher efficiency compared to regular filter sand include filter glass and ZeoSand, which can be used in place of filter sand.
To use filter sand alternatives, you have to completely remove sand from your filter tank.
I have tried most of these at one point in time, and none compares to DE filter media when it comes to boosting efficiency of the sand filter when used in the skimmer.
Since most filter sand alternatives cannot filter down to 1–5 microns, DE filter media comes in handy, unless you are going use filter glass that can filter down to 5 microns and is durable with long back-washing cycles.
Moreover, the other downside of these filter sand alternatives compared to DE filter media is the price factor, as the latter is relatively affordable—though it can only be used in the skimmer to improve efficiency of the sand filters.
Filter glass is one of the most efficient filter sand alternatives used today due to its efficiency over filter sand. It can filter down to 5 microns, unlike filter sand, which can only filter down to 30 microns.
Moreover, filter sand is relatively bulky, since the amount needed is much more than the amount needed for filter glass—which may translate to around 20% less media in weight compared to filter sand used in the same filter.
Finally, filter sand wears out very soon as compared to filter glass, which is more durable and can last three times longer than the filter sand.
Filter glass also reduces back-wash cycle, saving money on your water bill, and lengthens the life span of the pool filter.
ZeoSand is another filter sand alternative that can filter down much smaller debris than regular filter sand—but not better than filter glass.
ZeoSand has a decreased backwash time as compared to the filter sand, and a smaller quantity is needed for the same effect as filter sand.
Just like filter sand, ZeoSand lasts up to five years, which means filter glass is more durable than both ZeoSand and 20 silica filter sand.
Questions & Answers
Question: Can I pour the DE powder instead of the Sand in my sand filter?
Answer: Using D.E. powder in a sand filter is not quite advisable, however, you can use Clorox D.E. + Filter Aid (https://thesummerpools.com/products/diatomaceous-e... that is used in the skimmer to improve water quality by filtering out smaller debris making the water cloudy and metal components causing metal stains in pool or spa.
Question: When we started putting the D.E. Media and Filter Aid in the skimmer our PSI was 19. The first pound dropped the PSI to 15. The directions say to wait 5 minutes if the pressure hasn't raised 1 psi to repeat until it does. We have done 6 lbs and the pressure is remaining the same. The pool is REALLY milky now and I'm afraid to put any more into the skimmer. The pressure never did raise, only dropped. What are we doing wrong to optimize the pressure output of our sand filter?
Answer: This could be a clogged pump basket, clogged impeller, clogged pipe or clogged skimmer that won't allow for your PSI to rise. You can also check or troubleshoot your filter if it is a problem caused b filter default i.e allowing water into the pool without filtering it causes PSI to rise slowly, reduce or stop rising completely. If all is okay, some filters take too long like weeks before the PSI rises but will eventually rise, especially if you have a large filter.
Question: I ordered a large amount of Food Grade DE for a different purpose. Can I use it and follow your instructions versus buying pool filter DE?
Answer: No, food grade D.E. cannot be used in a swimming pool. D.E filter media is preferred since it's made with advanced water filters technology in mind.
Barack James (author) from Green City in the Sun on January 02, 2018:
Hi, if the water is stagnant and clean means the zeolite is not used and can still work to filter your pool water. You may have to replace it if the water pool remains cloudy or dirt.
RCriswell on December 28, 2017:
Looking for some info on a caring for a pool filter with zeolite.
I installed a sand filter last year on a converted above ground agriculture cement tank that's now a pool. I chose Zeolite over sand,
Due to medical reasons I had to leave the camp for several months. Upon my return I discovered that the filter had been taken down and stored in a shed - full of water. My question is if this zeolite media is still good to use after standing in water for approximately 7 months.