Any reason why I can't fill the bottom of my 55 with a couple inches of dirt and sand?

Question

It should be good for the plants....

Answer 1

It would probably be moved around by the filter and disturb the fish and then probably get sucked up by the filter.

Answer 2

None at all.  In fact, that's what many aquascape artists use to fill the bottom of their heavily planted tanks.  It's a great plant growing alternative that's a lot cheaper than fluorite or other purchased plant substrates.  An inch or two of soil on the bottom of the tank covered with sand or gravel to keep the dirt down so that it doesn't float up and cloud the tank water grows great aquatic plants.  Just make sure that the soil is good, sterilized dirt and that it doesn't have any additives or plant fertilizers in it because a lot of those contain ammonia or nitrates which are bad for your fish.

Answer 3

the soil and sand are probably not fish friendly. they have only just got to have the wrong chemical or stuff in them and its good night fish stock. ask at your local fish store for fish safe products.