I never used to do "regular" water changes, for almost 2 years I used straight out of the tap for everything, including the 3 water changes I did during that time.... 0 issues, other then I didnt notice alot of growth, but that could also be attributed to the 3 upgrades, 2 moves, and my constant need to tweek things for appearance ( I never let much settle in to do any growing.... and I also have always had 2-3 angels which may help with the lack of growth on some things lol)
Couple months ago I decided to finally hook up the RO/DI unit Ive had for over a year..... I have had cyano horribly, now gha and probably dino's too from the looks of it. All things I NEVER experienced before. I also started doing regular water changes of 12-20 gallons (180g display, w/ a 30g cube tired in on a 100g sump) every 2 weeks depending on what I felt like doing that day I decided to do them and the time I had.... I have noticed a little better growth on my sps but nothing significant, so I am going to try no water changes for a while and see if this algae crap goes away. IF it does I will have an RO/DI for sale LOL
Oh yeah, for tap I have used 2 different "city waters" and 2 different wells... current place w/ the RO/DI now hooked up TDS is high 400's-low 500's, used it for almost a year before hooking up the RO/DI and never had algae issues before.
I don't condone or recommend not using RO/DI it works for most people.... but the best piece of advice I have ever really learned in this hobby is that u need to realize every tank is different and what works for one person may not work for u and vice versa
