REDSTEVEO
Member
Clive your fish health and plant quality say it all. Quality!Feed lots of live food and Bobs your uncle.
I've had no trouble with cardinals and other tetras or soft water fish thriving in water similar to London tap water. As far as high NO3/PO4, please...
P. transvestitus - a notoriously difficult soft water fish. 750 microseimens, GH 26+, KH 15 + 5X EI dosing.
Marble Hatchets in the same tank
Ram in the same tank.
Nutrition, clean tank and healthy plants are the keys. I see no reason you cannot mix your current RO reservoir with tap and have them looking nice.
Cheers,
Steve