I have a bag of plum slate in my car, I am tired of gravel, so I thought I would try this instead, what do you think? . I personally think as it is larger than the usual gravel, it would be easier to remove all the fish poo from.
I dont think this is going to be too heavy, its them slate chippings you get for drives or whatever. Now if I was really techie I would design a piece of perspex with a air inflated cuff that went to the bottom of the tank and then stuck there, place two connectors each side of the tank bottom and force high pressure water from one end to the other, dyson eat your heart out, what a gravel cleaner that would be, watch as the poo goes from one end to the other and out........
Erm my pics are like kiddie scribble, ok try imagining at the bottom of each end of your tank having 2 connectors you can plug hoses into, one end ie the right side would be for putting a pressure jet line ( obviously not rocket fuelled) and then drop the left hand end ones into a big bucket, then put your perspex with cuff into the tank to the bottom and inflate so it seals the bottom of the tank of from the rest, and blast away with water. probably find the gravel and the poo in the bucket, but hey its novel and probably a fun way to clean the bottom of your tank out, just dont forget to look for the plants and shrimp afterwards . Oh and if your wallpaper starts dripping I accept no responsibility. just a completely daft useless idea I had.