Has anybody had issues with using plain old gravel in a planted tank over time? I've had a 46Bow up and running for about 15 months. It's relatively heavily planted and medium fish load. I'm at 2WPG, modified Estimative Index for ferts, and twice monthly water changes. Algea (believe it or not) has always been pretty much under control and plant growth has been good.
I'm cursed, however, with hoses and a filter (Eheim 2026) that seem to fill up with brown mulm way too quickly, and often seem to be able to see a bit of white haze in the water as the day goes on. The fact it seems to get worse as the day goes on implies it's algea and not bacteria. I'm wondering if the regular gravel (i.e. not a "good" substrate) is allowing the crud to creep down into the substrate and cause a buildup of bacteria, thus causing a heavier bioload on the system than it really should have. By the time I vac the bottom of the tank every 14 days there is considerable stuff that is on the gravel to be filtered out and I don't think it's just poop. It seems that the tank is making this brown stuff, and I suspect it's from a bunch of crap getting into the substrate and rotting (not food - I feed real lightly).
I've learned a ton from this board over the past year plus, and realize I really should have started with a good substrate from the beginning. I'm going to be doing a full teardown in the coming weeks and replacing the substrate with some good stuff, but I'd sure feel better knowing what's causing this major buildup of brown crud on the floor of the tank, in the filter, and in the hoses.
Do you think the less than optimal substrate could be to blame?