drilling my tank: Drain size and return size

[BSmitty22]

hi all
I am about to drill my 40 gallon tank. I have an overflow box that is large enough for two holes. I want to do a herbie style overflow so one will be a full siphon and the other an emergency. I also want to drill a third hole for the return. I plan on using a hydor seltz L40 (740 gph at pump, ~400 at 4' of head) for a return and I believe it has a 5/8" outlet.

I really have no idea what size holes to drill for the drains and return. Should one drain be larger than the other or can they both be the same size? I was thinking 1' for drains. I really need any and all advise here. What kind of pvc should I use. Flex tube or regular pvc? haha I know I am hopeless. Thanks to all who help out here.

[BSmitty22]

pictures from anyone would be nice to. also if anyone has used the seltz L40, I would like to know how it works for you. thanks

[Waddleboy]

Bulkhead size depends on what bulkhead you want. Heavy duty or regular but 1 7/8" and 1 3/4" respectively. But best way is too look at what the bulkhead says to use. I don't know enough bout the herbie system to say but I think when the tank is per drilled and one is bigger and the bigger is the drain... However I don't believe it's necessary. As for PVC it's your choice. Hard works well. I have heard flex tubing kinks and gt gross and can be a pain. Also what pictures you want?

[Putty]

I drilled mine using 1 1/2 bulkheads. I run PVC flex tubing to the sump.

http://img.photobucket.com/albums/v640/CLovaR1/IMAG0899.jpg

http://img.photobucket.com/albums/v640/CLovaR1/IMAG0884.jpg

[BSmitty22]

is it better to use bulkheads with slip on both sides or threaded on both or one of each?

[Waddleboy]

Depends what your trying to do. I like threaded on the outside because I can then screw things into it and make it adjustable. Easier for maintenance