Re: DE in a sand filter???

Originally Posted by
gwrace1
I recommend it because it has worked so well for us. We had no water available to us other than from a very hard water iron rich well.
Zeolite can remove heavy metals (including calcium and iron) from the water in much the same way it removes ammonia (and in fact is sometimes used in water softener units as the ion exhange resin) but it is not nearly as effective as other water softening resins and if the concentrations are high it will require regeneration once it's capacity has been reached ...see below about regeneration of zeolite. Also water softeners are regenerated with the brine solution ususally at least a few times a week so this ability will quickly diminish!
We wanted the maximum filtration we could get from the filter with the least amount of maintanance. We got that with the sand filter and Zeolite.
We knew the pool was going to get it's share of air borne debris from the various trees in the area. We also wanted to put as little effort as possible into pool maint. We got that from the SWG, Poolskim, Pool Rover, sand filter with Zeolite. I've had to backwash the filter one time since the pool was installed in early March.
I don't know that you can justify the cost over DE in sand. However here are some things to consider.
1. You only use have as much Zeolite as you would sand.
That is by weight, not by volume. It weighs about half as much as sand. The price per pound is much higher than sand. A 50 lb bag of sand sells for about $6 so 6 bags would be 300 lbs and costs $36. A 150 lb bag of Zeobrite (equivalent to 300lbs of sand) sells for about $75 dollars...more than double the price for the same amount needed!
2. You backwash much less frequently which conserves water and chemicals and is easier on the enviornment.
This is probably true since the rough surface of zeolite can trap more dirt than the smooth surface of sand. One plus for zeolite. However the grains are actually up to 3X larger than sand grains (up to 1.5 mm while sand is about .5 mm) and that will reduce the mechanical filtering ability so you might only be breaking even here.
3. Zeolite is a natural bio-degradable medium so can be disposed of safely which includes using it in your garden.
Last time I checked DE was also a natural medium. Zeolite does not biodegrade. It is a mined mineral and is a hydrated (containing water) alumino-silicate oxide (contains both aluminum and silicon). Sand is silicon dioxide (silica). DE is the fossilized shells of prehistoric freshwater and marine organisms and is primaily silicon dioxide(silica) with a smaller amount of aluminum dioxide and other minerals present. All three are mined. Non of them biodegrade. All of them can be mixed into your garden but all they are basically a form of sand (silica).
4. The reduced labor and maint. hours should add up to some value.
remains to be seen. With the necessity of 'recharging' the zeolite yearly (for chlorine pools) with an acidic brine solution it might be more labor than sand.
5. Zeolite is renewable. When the filtration qualities diminish you recharge the medium with a salt solution.
Zeolites main advantage is the ability to adsorb (not absorb!) ammonia compounds. It has been used for aquarium filtraton for this reason for many years. It acts like an ion exchange resin in your water softener and is functioning as a chemical and not mechanical filter medium in this respect by trapping ammonium ions. When it cannot adsorb any more it can be regenerated with an acidic brine solution (concentrated salt solution and acid). As far as cleaning it of particulate matter (mechanical filtration) that is what backwashing does so it is no different than sand here. Plus you have the added step of 'recharging it yearly and have the brine solution to dispose of....good way to kill the grass!
It is "supposed" to outlast sand many times over. Our neighbor has a never ending sand pile as he replaces it every year (softswim user).
Can't compare biguind (SoftSwim) to chlorine here. Even on the Zeobrite website they recommend cleaning the zeolite medium MONTHY with the above cleaning solution when using bigiunide. The makers of the various biguinde systems (Baquacil, SoftSwim, Revacil) also recommend monthy cleaning of sand when used with their systems and yearly reppplacement. Seems like it's exactly the same. It will still probably require yearly replacement (or perhaps more often) just like sand since since biguinide gunks up and ruins filter material and the 'pores in the zeolite will certainly get gunked up fast.
6. I don't think a cost of $40.00 for a 50lb bag is all that expensive comparied to the per ounce per pound cost of other pool chemical products.
We needed 175 lbs for a total cost of $160.00 with some left over.
Sand at $6/50 lb bag would have cost you $24. Even if you paid a premium price of $12/50 lb bag of sand that is still less than $50 total! Think of all the bleach you could have bought with the left over $100-$125 dollars!
Just some things to consider.
Just a few more things to consider!
Last edited by waterbear; 07-13-2006 at 08:01 PM.
Retired pool store and commercial pool maintenance guy.
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