kelvyn, so u decided on ur outdoor filter?

i am also looking, dunno membrane or those many layers(rock) filters better suited..my condo have too much sand/stone coming in. clogging up all my taps, every 2 days need to open and wash. so mah fan.

i was looking at alphamax since they have like many many counters all over kl, but it wasn't cheap..and is too big to be installed at the walkway.

wdarke and kelvyn, yes dunno about the backwash. but if really do backwash, there's like a small longkang..so water can flow there. I guess i just don't do it while ppl are walking around in the walkway. Then just mop it dry after backwash.

i think sand filter is more suitable right, for my case to keep out the stones/sands? is it possible to get something below 1k?

the other thing is..can't install big filters in condo, as it takes up space in the walkway.