Loaches Online Forum

I'll let it cool down, just in case. Thanks!

That is the right idea, but shop in the hardware store, or a company that specializes in water purification.
When such things are sold for aquarium use I think they are too expensive for the gallons they produce (as you found out, expensive cartridges) and may do a poor job.
When you are talking to people whose job it is to sell you a reverse osmosis unit for household use you can demand information about expected life of the cartridges (It is variable, depending on local water conditions) and many other things that should add up to how much will this unit cost to operate per gallon of water produced.
If your local water is all that bad you might be better getting some combination unit that has a water softener or some other sort of pre-treatment filter, followed by the RO unit.
I had one of these, and found the water that came out of the pre-treatment filter was great aquarium water, and I only used the RO water for a couple of really particular tanks. (Breeding Rams)

Part of the use of such a unit is to provide better drinking water, too, so do not think that it is JUST for aquariums.

Hey, that's a great idea! I'm sure Lowe's or Home Depot sells them. I currently use a PUR faucet mounted filter for drinking water, and those cartriges aren't exactly great anymore. Good point, I'll keep an eye out, thanks!

I know the HD close to me sells them, several models with different features. Ask the local people (who are familiar with your local water) for advise.

I'll do that, thanks again!