Protective layer on top of sand against turbidity?

Hey guys!


I have a bit of an issue with my tank; it's a 60 gallon tank in which i used a layer of worm castings underneath a layer of sand.


Here's my problem: the wormcastings I used have a really, really small grain size and therefore leak through the sand; since I did not use gravel, any accumulating mulm mixes with the castings and lies ontop of the sand. Now, the castings aren't just a small grain size, they are very light too (or, you know, lots of exposed negative charges), so any critter associated movement keeps them suspended. The result is a really turbid tank (especially after feeding) with dirt covered plants.


Unfortunately I cannot install an external filter, since I put the tank too close to the wall; a tube won't fit in between ( >.< ) I tried using internal filters but the bioload is waaaay too high; even filter tubes won't work, the castings still form them into a brick after a few days. I bet some of you who use the original walstadt method know what dirt does, instead of passing through filter sponges.


Anyways after 2 years I finally thought of maybe helping all the dirt form a heavy layer that keeps itself down. So here is my idea on which I am pursuing input from you guys. I figured I could dose way too much Iron for the next few months; since Iron flockulates reall nice (Fe2O3??) the big, complex pieces might be able to catch a lot of fine dust that drags them down. Also they would lay on top and protect the fine stuff from turbulent movement of the water collumn.


So here's my questions: Is there a more efficient way of doing this than just dosing lots and lots of micro ferts? Do you guys have any other ideas of doing this that I could use instead or combine?


I don't wanna break my tank down btw; I don't have enough space for keeping fishes in huge buckets for a few weeks.


Anyways, thanks in advance! Any input is appreciated by you guys


Nemo


Oh by the way; fun fact: you know how in an aquarium mulm usually aggregates into these larger fluffs on its own? Not in my tank, it's all fine dust. I assume it's the wormcastings that prevent any aggregation? Damn you high CEC!