Would like to get suggestions on the amount, type, depth of substrate that would be good for this tank. Little apprehensive with using flourite, onyx sand, because of nutrients leaching into the w/c, and giving me problems with the fish. Seem to be running a fine edge here-I don't want to screw up the w/c, but the plants need nutrients to flourish. Thought about using pots-anyone have a good substrate formula for an aquarium pot? . All thoughts and comments would be appreciated!!

Flourite doesn't leach nutrients, because it is inert. If you do water column fertilizing the plants will do fine without nutrients in the substrate, even though some might do a bit better with some substrate nutrients. Onyx sand leaches only hardness causing "nutrients", as I recall, which would only be a problem if the fish can't tolerate the higher hardness.

Greg at SeaChem is letting me use some of their new Black flourite.
Like the normal stuff, it's leach free.
ADA is about the only thing that leaches nutrients or soil based sediments or Jobes sticks etc etc. Onyx some KH/GH, but it's CaCO3, calcite, so that's to be expected to some degree.

What is the water change routine as it stands?
Most Discus w/c routines work very well with plain old EI dosing, which was worked out originally on a 90 gal with 6 Full sized Discus+ other cories, ottos etc. I just did 1x a week 50-60%, you can do 2x 30% etc, or 2x 50%.

The issue is not the sediment, the issue is all the NH4 from the food, that is why you do the water changes(not really to reduce the PO4 which is not a toxicant even at very high levels,, and NO3 needs to be very high also), adding plants reduces NH4 via direct uptake and adds O2.


Regards,
Tom Barr