How are your fish now? I would try to get plant root tabs for the amazon sword because they are heavy root feeders and the wisteria would appreciate the root tab. Good luck. :thm:
go get yourself some osmocote and make fertcicles. drop 6-8 granules in each slot in an ice cube tray, just barely cover them with water, freeze and shove one or two under your sword. it will be a lot cheaper and probably give you much better results than any commercial root tabs. plus they feed for several months as opposed to just barely one.
from what i'm seeing $5 in osmocote will replace over $100 worth of fluorish tabs... very easily.
well, see... you have a gravel substrate. this means there's inevitably voids between each "rock" that water certainly flows through. this tells me that some of the ferts would certainly leach into the water column. so i'd say in your case... yes. maybe not so much if you had a sand substrate but it would certainly still help limit what the sword would need from the water column... which in turn SHOULD still help. i would still at least dose micros in the water column.