hi all,

i have read through the whole tread, from 2012 til the last Jul 2015. but some details about filters are not so clear.
As in the market, outdoor filter have few types, Ultrafiltration membrane filter, sand filter, and like 3M, not a membrane nor sand type.
what is the maintenance between these three types? 3M require to change cartridge every year, sand filter is backwashed hence it only require to change sand after 3 years. Then how about membrane filter? is it maintenance free?
Besides that, i looked through the spec UF membrane filter and most of membrane pore size is 0.01 microns. is this meaning that after install membrane filter we don't have to install indoor water filter as 0.01 microns have already closed to RO water? in term of water pressure, which is better?
i do not really recommend to drink RO water because it is too clean that nothing is inside, my personal opinion. but, how about 0.01 microns? is it still sustaining the minerals inside? hope someone could answer. tq tq..