Drilled tank water change system

[dafunk5446]

Hello I have a 40 gallon breeder that I was planning on using as a reef. It was going to be a reef tank so I had holes drilled in the back of it about half way up. I am however getting out of the reef hobby. So I was going to use it for a couple discus. I think I have figured out a way to make the holes work to my advantage. My plan is to be able to turn a ball valve and drain the tank, almost 100%. It will be sitting next to a floor drain so this makes the most sense to me. This is where it gets confusing. I will be using bulkheads on the holes, and on the back I will run 2 pvc tubes (one for each hole) down below the bottom of the tank to another horizontal pvc tube. I will attach a ball valve to the open end of this tube to be able to dump water from the tank. On the inside of the tank pvc will run down from the holes to the bottom of the tank. These will be attached to two straight bars (again one for each hole) that run along the back of the tank. On each of these bars there will 6-7 pvc tubes running towards the front of tank along the bottom. On the bottom of these tubes will be 1/4 inch slits cut in the tubes every inch or so. So when the ball valve is turned open, water/waste is sucked through the slits on the tubes back up through the holes down the pvc tubes and dumped down the drain. Does this sound like it would work? Sorry if it is confusing if pics are needed let me know

[Polar_Bear]

I have a system someewhat similar, but with one 1" PVC instead of two 1/2", it works well and will drain a 75 gallon tank in under 5 minutes. My only other comment is that spacing the slits that far apart will result in greatly reduced water flow, what I did instead was rout a 3/8" slit into the pipe going almost totally along the pipe (I left the ends intact for stability). One other thing to note is that it helps clear debris if you start refilling the tank just before it is totally drained, this causes almost all "gunk" to be taken into the syphon pipe.

[dafunk5446]

Sweet, I would be using 1" not 1/2", I was kinda worried I would loose alot of flow if I cut the pipe like that. I was think some thing similar to your method to but then I remembered my spray bar on my reef. I balanced the flow across a bar like that by drilling consecutively larger holes down the tube. I might have to test a couple different methods and see what works best. How far apart do you have them spaced? I was also thinking about starting to fill it before it finished draining. I have a 80 gallon rain barrel that I use for R/O on my reef tanks. It has a 850 gph pump with enough hose to reach it so I should be able to flush it out really well.

Another question I have is my filter. I have a fluval 305 and I was also going to use this on my reef tank. So I made a spray bar for it that has a real nice even flow across it. Nothing strong just good turnover. I was thinking about attaching the intake of it to the pvc on the back of the tank. So It could always be sucking the funk off the bottom of one side of the tank. I would just leave the stock foam filter in, but would fill the baskets with 4 different pore sizes of foam (decreasing pore size going up the baskets). Then in the last compartment I would have the option to run other media's if needed. This would be cleaned weekly. Sound ok?