causes for excess detritus.

It could be as simple as insufficient flow throughout your aquarium.

+1 on insufficient flow. could also be from an overstocked tank. I remember from an old thread how tom barr cleaned dwarf hair grass: comb it like hair, then siphon the detritus that rises. what kind of filter are you running?

eheim 2217 on 33gallon

in my experiences the most common reasons for excess detritus build up are generally very simple.

1 not enough flow through out the aquarium. Now, just having a bunch of flow from your filter doesn't mean its throughout the aquarium. having just one source of flow with plants can very easily lead to dead spots.

2 not having enough mechanical filtration to handle the detritus, either due to low flow through or just lack of actual floss or other mechanical media.

3 over feeding or overstocked tank making the filter insufficient for the amount of detritus.

I would look at the problems in the order I listed as usually in my experience I listed them in the most common order of occurence.

reefkprZ summed it up pretty nice. If you do need more flow, try a powerhead.koralia nanos work pretty well