as info read also this: Q: What is the difference between a Sand, Cartridge, or D.E. filter
A: Sand – Filter Range 20 to 40 microns. The oldest and most popular method of filtrations is sand. Sand filters use a special filter sand, normally .45 to .55 mm (also known as pool-grade #20 silica sand), because it has sharp edges that serve to separate particles, allowing filtration to take place. Sand filters are the least expensive of the three types of filters but only filters particles down to 20 to 40 microns in size.
Cartridge – Filter Range 10 to 20 microns. Cartridge filtration has been available for a relatively long time, and recently has begun to enjoy rapid growth and acceptance. When water passes through a cartridge filter, dirt is screened out at the surface of the cartridge element. When clean, the element will trap larger particles, with finer particles being filtered out as the pores of the element become clogged by the larger debris. The cartridge element can be removed and cleaned by pressure washing inside and out with a garden hose.
D.E. (Diatomaceous Earth) – Filtration Range 1 to 3 microns. Many pool professionals consider D.E. filtration to be the finest, because it is capable of removing smaller particles than either sand or cartridge. Diatomaceous earth is a porous powder with microscopic openings, that, when magnified, look like tiny sponges. Clear water can pass through these openings but particles, as small as one to three microns are trapped the first pass
through the media. All D.E. filters have internal elements that become coated with D.E. It is this “filter cake” that strains dirt, dust, algae and some forms of bacteria from the water. Similar to sand filters, when a D.E. filter becomes dirty, it is cleaned either by back washing the clogged D.E. to the “waste” line or regenerating and draining. To restore filtration, a fresh “charge” of D.E. is added to the filter.
my pump and filter from sta-rite ( american made) has cost me 36.000 baht ( set) , price now 40.000 baht...,
1 HP pump adequate enough for my pool from 10 x 5 M...i clean the filter about every 2-3 months depending the usage of the pool, using each time ,2.7kg of DE powder, 1 bag 20kg = between 900-1200 baht ....
in my case , i take out the element , hose it clean with the water hose , replace , and add the DE powder, all this takes less than 30 minutes , but for some maybe all ready to much work...
i have a friend , who has a sand filter pool ,( now with zeolite) his water never comes near the clarity of my pool + he always has some problem..., he is now planning to follow my advice replacing the sand filter by a DE filter , so he also get rid of all his headache...
i am using a floating chlorinator, with 90% chlorine tablets inside, very easy and never had problems...
and the automated chlorinators use in a saltwater pools are expensive ( if you buy the good ones ) , you can buy a lot chlorine for this over the years , only saltwater is more skin friendly than chlorine , but i think i will not die from this...
and indeed , stay away from all things made in china....
as of skimmer system or overflow ( and surely not the coffee bag system , in the stair)
depending the size of the pool , if go bigger than 10x5m i would advice an overflow, you can also make a
semi -overflow,up to 10x5m skimmer system ok...
no matter what system you choose , as long as you are happy..
good luck....
