ok, so i just picked up a 135 gallon to replace my 60 gallon. i've been thinking about doing this tank design for awhile and i wanted some input about it.
i am going to make a rock wall as described in this diy...
Do It Yourself Aquarium Projects
also i wanted to create a void space under the gravel as a sort of under gravel filter, i duno, i think i just want to see if this was possible. i was going to use an eggcrate with window-screen to support the area above the void but i realized this might now work since i want to use sand so im thinking maybe i can lay a thick foam pad on top to stop the sand. here's a diagram:
as you can see i will use one of those long air stones (4ft) to circulate water under there so it doesnt become stagnant, also the air bubbles will rise up behind the rock wall helping to move water within the rockwall caves so that the water doesnt become stagnant there as well. i will be making notches on the back of the rock-cave partitions so air bubbles can move through there as well.
the original design was for a perfectly rectangle tank bottom but the tank i picked up has an overflow on the right side of it, i was wondering what the effects of a piece of foam inside the tank might do to it, i realize it may gather organic matter and might eventually become a danger to my fish but i was wondering if this was negligible since the tank is so large. i will be filling the overflow with bioballs and my 35 gallon sump is also packed with bioballs so i dont think i will worry about chemical build up.
i didnt include it in the picture but the bottom void eggcrate will be supported into that incline by different size, evenly spaced pcv pipe connectors that i will silicone to the bottom of the tank. larger ones in the back while the smaller ones up front of course. since the opening limits the size of objects i can insert into the tank i'll be breaking up the eggcrate and then zip-tie them together once they are inside the tank. this is fresh water tank.