Well...for a while there I tried tap water with nothing else...I got some slime build up around my pump and in the pins of my CPU block. I fought that for months...then I found a silver dollar in the "random" stuff box and tossed it in on top of the inlet of my pump...This seems to keep the slime down to a managable rate of growth. I still have to break down and clean out my bong and CPU block every couple of months but it seems to get to be less and less and the summer rolls in and the loop is starteing to get use to whats going on in there or something.
Now...Nub uses a tablet he found at home depot or somewhere and he says he has absolutely no problems...they are cheap and I would recommend them to my method only because it took me a long time to get the water just right in there lol. I don't want you to get frustrated and throw out your bong just because of a bit of slime.
As far and the solids in your water causing corrosion...I think it depends on your water...The PPM of my water is 157PPM and as it sits in the res it settles and goes to about 60PPM. There is no rust or corrosion on my block yet and its been 9 months or so.
I did have a filter that I would toss in there every once and a while to try and filter out the funk but it seemed to just bring more in.
I am guessing if I left it in there full time (not running) then it would be more effective though.Edited by DIRTYDUCK - 7/12/09 at 11:14am