Originally Posted by GeriDoc
That is likely true, but not the whole story. I have been in marine fishkeeping for more than 30 years, and the use of RODI is fairly new to me, too. However, I have noticed that since better water has become common, fish live longer - lots longer (when I began, a 2 year old marine fish was pretty much unheard of, now 5-10 years is pretty common), and the grow much more (adults are actually adult sized. I can remember having a volitans for 3 years that was 4" when I got it, and the same 3 years later, despite some heavy feeding). So...two years with no problem means that your tap water isn't too bad, and that it will take a little longer before the accumulation of contaminants reaches a critical level. With RODI it just takes much longer, if at all, to get there.
You could be right.
I have 6 damsels, 2 foxface ,a toby puffer, 20 snails,6 hermits only lost 1 damsel during cycle. They are really active so I guess they're happy.
I feed my fishs raw: shrimp, scollop, cut fish, chop cuttlefish all soak in vitmain before feeding 2x a day, everyone of these fishs have a "beer stomach".
I guess good nutritions and so-so quality water Compromise each other.