Diatomaceous Earth Filters, Disadvantages :

The first and probably greatest disadvantage to owning a pool with a DE filter is that is not trivial to maintain, in other words, as compared to a sand filter, the DE filter is a high maintenance item. This maintenance issue can be broken down and organized into the following two sections.


Maintenance issue # 1 :

Elaborate Backwashing and Recharging Techniques

The DE filter, like the sand filter, can be backwashed to clean it out. However, this backwashing effort is different. The DE filter must be backwashed three times in a row to remove most of the old DE media. You have to turn the pool pump off. Move the backwash valve into the proper position, and turn the pump back on. At this point, the water flow inside of the filter will reverse direction, washing the filter grids clean of the old DE powder. This dirty powder will then leave the filter and travel down the backwash pipe or hose and exit into a pit or perhaps the lawn.

Once the backwash water has turned clear, you turn the pump off and move the backwash valve back into it's original position. Turn the pool pump back on. The pump will now push water back into the filter and whatever old DE powder that remains in the filter will begin to collect again on the grids. Wait for five minutes, turn the pump off, move the backwash valve back into the "backwash position", and turn the pump back on. This time the water from the filter will still be dirty, but won't take as long to clear. This process needs to be repeated one more time, for a total of three backwashes. You will notice that the during the last backwash, just a little puff of dirt will exit. Whew!....But we aren't done yet!

You have to get the bag of DE powder, the one you bought at your local pool store. Oh! I forgot to tell you about that. You need to buy DE powder for this type of filter. Well, at least it is cheap. Also, pick up some good dust masks to wear while you are working with this powder.

According to your DE Filters manual and following the instructions on the reverse side of the bag of DE, you will measure out and use at least several coffee cans worth of DE powder to do what is called "recharging" the filter. Note: There is a specially made plastic scooper that holds one pound of DE powder. Pick one up at your local pool store.

This " recharging" is accomplished by mixing the prescribed number of cans of DE powder into a five gallon bucket, filled with water. With the pool pump running, take the skimmer lid off, lift out the skimmer basket, and the diverter valve. Then slowly pour this mixture into the skimmer. A shortcut that I have used is to just put the cans of DE powder, one at a time, directly into the skimmer, while the pool pump is running. Be aware that this shortcut really makes a mess, and you better be wearing the dust mask during the whole process, from start to finish, because there will a lot of dust in the air. The mixture will flow through the pools suction line, back towards and through the pump, and once again collect onto the septum of the filter grids. You now have a new and clean DE filter media for your pool water to flow through....

Unfortunately, not all of the old DE powder has gotten out of the filter! It never does. When you backwash a DE filter, there is always some left behind. You can get by with backwashing a DE filter perhaps three times over the course of a year or more, depending on the weather. After that, guess what? You have to disassemble the DE filter and clean it out by hand. Oh! Joy of Joys!

This disassembling process is quite involved and it is at this point where mere words fail. I will have to create a video and provide detailed instructions, or provide a link to a youtube video at this point. For now, just do a Google video search for cleaning out DE filters and you will probably find something to look at. I will talk about this manual clean out process in a later post.

There are a series of warnings in connection with diatomaceous earth powder, that I feel a need to talk about:

DE powder scatters like a fog when disturbed, and rises into the air with very little wind. Do not allow anyone to be close to you as you are working with this powder! As you fill your can or scooper with DE powder, the powder will float in the air around you. So be sure you are using your face mask. A lot of people, including professionals, try to get around the wearing of a dust mask. They get the bright idea to just hold their breath. I too have tried to skip wearing a dust mask. Sooner or later you will screw up and draw air filled with DE powder into your lungs. Twice, I have spent several days coughing and spitting up white DE powder. Guess what? You can't get all of this stuff out of your lungs. It stays in there for the rest of your life and fuses with your lung tissue. Use a dust mask.

Do I need to warn you against leaving the partially empty DE powder bag around where children might have access to it? Yes, I do. Put the bag high up on a shelf, preferably with a bunji cord wrapped around it. Warn your children or grandchildren to stay away from this stuff.


Maintenance issue # 2 :

Fragile Internal Frame and Grid Work

The second big disadvantage to owning a DE filter is that the internal plastic grid work, and the grid work's septum are fragile and they just don't last nearly as long as the internal parts of a sand filter. The grids, themselves, when viewed from above are designed in a spiral pattern to maximize filter area within a confined space. It is not uncommon that after as little as two years, during a clean out, you may notice a tear or a hole in the fabric of the septum of one or more of the grids. The ribs of the septum frame may also be broken. Any grids that have these defects are going to have to be replaced. Any twigs that get into a DE filter may puncture the septum, and that small puncture expands into a hole. If you neglect regular backwashing of your DE filter, the grid work will tend to break or be crushed. If you neglect cleaning out your filter, "bridging" between grids may occur, this increases the pressure on the grid frame and can break it.

So, with all of the previous information, it seems that a DE filter is a real pain, and it is. Do I still recommend this type of filter? Yes! I will still recommend a DE filter to anyone who is not afraid of learning something new, who is not afraid of getting their hands dirty or to someone who is not afraid of paying someone else to do the dirty work. It is just that a DE filter does such a very, very good job at filtering your pools water, that all the hassle is worth it. Ask anyone who owns one.

The next post will cover filter pressures.