All those water para flucuation's finally caught up to you I see 8O .
I had a blue ram get a touch of ick in my planted tank, thankfully that was the only fish. I increased my water temp from 82, up to 84 and did 25%
WC's for three days. Lightly vacing the gravel each time. Ick needs a host to live, if it runs around in your tank at high temps for a day or two, without finding a host (healthy fish) it will die. Check out Ally's right up on ick here on AA.
As for chemical's, I try not to use them as much as possible. My tank had a very slight case of ick (1 fish), raising the water temp , daily
WC's did it for me. Not sure how bad your's is.
Now heres where things get tricky. Seeing how hard your water is and your mixing
RO water, that is probably the source of your ick. Best I can recall, several people told you not to lower your
GH,
KH to fast with the
RO, or you would stress your fish
Best thing you can do is get your water para's stable. Flucuations all the time stress fish heavily, leading to health problems and ick etc.... Your going to have to make sure when you do
WC's with the
RO, that the para's (Temp,
KH,
GH,
PH) are as close as possible to your tank.
Whatever you do, do'nt add a lot of salt to your tank. It will damage your plants and kill your shrimp.
Are'nt planted tanks fun

Just wait till you get your dry ferts and you have your first algae bloom 8O