You said that it takes like a day to fill a 3 gal tank up rt? How does and RO system work? Put water in it and then turn on and is a drip system or something?
LOL...only half a day, I can fill it, drain it and it will refill after about 8 hours, then I get bored with it and leave a 5g jug connected, as it fills up, I pour it into my 37g plastic can (marked fish only).
I use Culligan water, I get charged 39.99 a month. They service the unit and replace all the filters, so I really don't have to mess with it. I do have a TDS meter and the system has a faucet with a light on it, if the light turns red, the TDS is above 10, and I can call them (it has never happened in the 10 years I have had it). I have a 3g jug I fill and put on my bubbler/dispenser for drinking water, and I use the little faucet for cooking or attach a hose to drain it into my jug.
Tap water drips very slow through 5 filters, then I have a little 3g holding tank under the kitchen sink, once filled the drip stops and the RO just sits in the holding tank until I use it. The small faucet on the kitchen sink is in a space where a soap dispenser used to be, I can get RO water from the faucet, or I run a flexible hose from it to my jug.
The original cast for installation was near $200.00 (actually about the price to buy my own unit) and like I said, I pay $39.99 a month, but that means I don't have to mess with it, and if anything goes wrong, THEY have to fix it, or replace it. They swap out my filters, and if my TDS is too high all I have to do is call them. Last test read 4, it isn't 0, but it's 100% better then tap water, or hauling jugs of water for my tanks from Walmart.