Simply Koi and More Koi

Thnaks for the info. Will check the TDS on ym pond with my meter at some point now, though I don't think I'll be making the switch to RO water anytime soon; I've only got a 50gpd unit!!!!

Good point! All the data, scientific and aquacultural, I've seen for common carp says they prefer a neutral to slightly basic water of 7.0 - 7.5, but are very adaptable to other conditions. I'm of course not saying accepted wisdom is always true, but AFAIK, most rivers in temperate areas seem to be ...

I'm really interested in why people think RO water makes such a difference for koi (I'm not, for a second doubting the results, just wondering why). I use RO on all my tropical tanks and it makes a huge difference to fish health/colours IMO, but they are all soft water fish. AFAIK koi don't seem to ...