I set up a 55g low-tech tank in April. It was really a complete re-do of an existing tank because I moved. Heavilly planted with ferns, crypts, and a sword. 1.75 wpg of T8s.
I put in some Osmocote, about 50% of the bottom covered one granual deep, toped with about an inch to an inch and a half of Vermiculite, capped with 2 to 3 inches of pool filter sand.
Half the crypts melted to death and never came back...but half are still there and chugging along, not as great as I might have hoped, but surviving.
Originally I was running two bottles of DIY CO2 but gave up after awhile...when I got busy this summer.
Kinda neglected the tank over the summer, house is not air conditioned. Lost some fish (Florida Flag Fish) which I attributed to the tank getting into the low 80s daily for about a month.
Put in some new tiger barbs since they take heat better, but they're dying too. So i tested the water. Nitrates off the charts.
Did some water changes. 75% to start, then two 50%. Also cleaned both cannisters, figuring they are kinda nitrate factories, and this might slow them down.
Nitrates are still off the charts. Tiger Barbs still dying. SAEs seem completely unaffected either by heat, now past, or nitrates. No algae problems either.
I'm going to continue water changes I guess, but, now here's the question. I've not disturbed the substrate since setting the tank up, but as it's just over 4 months I'm wondering about the Osmocote. I assumed as it released it's stuff the Vermiculite would bind up what wasn't being used by the tank and make it available to sword and crypts. Is it possible that the Osmocote, now completely dissolved, is being released by the vermiculite, or just not bound and that there's a very large supply of fertilizer seeping out the substrate that I'll never stop?