Switching to RO...

under the sink is a no go...i promise you i have thought of EVERYWHERE lol my lfs is just 5 min away and my tank isn't very big so just buying it from there isn't a problem..now that you mention it..doin one big water change does make more sense..I'll stock up on water this week and next week i will do one big one

is there anything i should add when i start regular top off's with the RO? I seem to remember reading about people adding trace elements or something because there is nothing in the water

 

Don't add anything to it. Pure RO/DI water. When it evaporates from the tank, the only thing that evaporates is the H2O so the only thing you want to put back is H2O. You see people that add Kalk to the top off water but that is simply using the water as the delivery method.

If you change 20% each time, the first time you end up with 80% of the old water. Next water change, you take out 20% but its only 16% of volume (20% of 80%). The next change, you have 64% original water. You change out 20%, that leaves you at ~50% since you took out 20% of the original 64%. So it takes 3 water changes and more water to get 50% of the original water out of the system.