Drilling/ Plumbing a 40 gallon tank

B

Bigsauce

New member
I'm slowly putting together a 40 breeder dt and had several questions regarding plumbing a tank. I've done google searches and scanned the forums but couldn't find the exact answers. So here they are:
1.)Should the overflow and return pipes be of the same diameter? I was planning on using 1 inch bulkheads.
2.) Do I have to use an overflow box if the overflow is drilled or can I just screw in a strainer?
3.) Some people drill 2 overflows, how does this work, do the two pipes join into one?
4.) What is a good height for the overflow and return?
This is going to be my first drilled tank and I don't want to mess it up. Any additional comments about plumbing along with answers and links are greatly appreciated.
 
Bigsauce said:
I'm slowly putting together a 40 breeder dt and had several questions regarding plumbing a tank. I've done google searches and scanned the forums but couldn't find the exact answers. So here they are:
1.)Should the overflow and return pipes be of the same diameter? I was planning on using 1 inch bulkheads.
2.) Do I have to use an overflow box if the overflow is drilled or can I just screw in a strainer?
3.) Some people drill 2 overflows, how does this work, do the two pipes join into one?
4.) What is a good height for the overflow and return?
This is going to be my first drilled tank and I don't want to mess it up. Any additional comments about plumbing along with answers and links are greatly appreciated.
Click to expand...

1) probably not. If they're the same size you have no room for error. keep in mind the drain is using gravity and the return is powered. if they're the same the path of least resistance will most likely be over the side of your tank. There are pros that know the math on this, but I go with 3/4 returns and 1.5" drains (or maybe a 1 inch return and two 1 inch drains). Double the return might be the rule of thumb, but I'd want others to chime in.
2) You want an overflow box to skim the surface of collecting lipid waste. If you only have a strainer under water you will develop a nasty oil slick that will kill O2 exchange. Google Durso standpipe or Herbie overflow for a visual). I used an acrylic HOB overflow box and simply cut the back off it and silicon-ed it over the bulkhead with the teeth at water level. (see my 45 thread below for more detail on that if you like)
3) you probably don't need two overflows in a 40b, but it is sometimes good to have two for redundancy (see Herbie overflow ((just a coincidence that it is my screen name))) Some will say they should rejoin and go into the sump, but on my 20l build I have them separate. one goes into the fuge with a ball valve for slowing the flow through there and the other goes right inthe the skimmer section. This is a hotly debated subject, so it's probably whatever makes the most sense to you.
4) high enough so your water level reaches an eye pleaseing level (just over the bottom of the top frame) but low enough that you don't overflow your tank before the water runs over the teeth and out. This is sort of an art and really depends on the way you end up plumbing it and the volume of your pump.

I hope that helps and maybe I'll cause others to chime in to correct any ignorance I have spewed. Good luck and keep asking questions and googling everything before you do anything.
 
Thanks Herbie you helped a lot. Right now I'm thinking about drilling a 3/4 inch return. For the overflow I'm looking at glass-holes 700gph overflow kit. Any suggestions on what type of return pump to use? The pipe is going to be 3 feet vertical, and probably a few inches horizontally. There are going to be 2 degree elbows, a check valve, a ball valve, and a union. Is there an actual mathematical formula I can use to calculate how many gph the pump should be after head loss? and finally, just to get this right, the return should match the overflows gph right? Again, thanks for chiming in. I just want to get everything right before drilling the tank and setting it up.
 
if you are going to hard plumb your tank with pvc then make sure that u put a T after the overflow so its really quiet, if u do a 90 then you get the gurgling noise that i have. Good luck il be follwing this build as i just set mine up.
 
krocky12 said:
if you are going to hard plumb your tank with pvc then make sure that u put a T after the overflow so its really quiet, if u do a 90 then you get the gurgling noise that i have. Good luck il be follwing this build as i just set mine up.
Click to expand...

Thanks for the tip! I'll be sure to incorporate that.
 
Don't forget that when you drill a glass tank to keep it structurally sound, keep the hole a minimum of 2.5" inches away from the edge of the tank. Plus this will be high enough to skim the top of the tank.

We have many tanks at the shop that are drilled and we just use the screw in strainer. You can also control the level of the inside of the tank by positioning the strainer properly.

And definitely use a durso standpipe to keep from gurgling.

Feel free to drop by and check out Mark's work and pick his brain.

~ Margaret
 
Thanks for the tips/suggestions everyone. I decided to buy the 700gph overflow kit from glass holes. It was a bit pricey but since I'm not very familiar with overflows I thought it would make things easier for me. As for the return, I'm going to use 3/4 inch piping with a mag7 pump. What do you guys think, any additional comments, critiques or suggestions? Again, thanks for helping me understand overflows/ plumbing tanks.
 
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