DYI Standpipe
 

so i have an internal overflow on my tank with a 1.5" drain hole on the bottom of the tank, then goes into a ball valve to control flow into the sump. problem is its louder than all hell, so i looked into ways to silence it and seems like a stand pipe is the way to go.

my question is since its only a 35gal tank with a 1.5" drain hole should i keep the stand pipe at 1.5" or should i go bigger, or smaller?

keep in mind the overflow chamber is about 18" high and 3.5"x3.75" wide...

What kind of standpipe are you using, you shouldn't be using a ball valve unless you have more than one drain. With one drain and the proper standpipe it should be quiet and if you do have a ball valve it should stay wide open and you should only close it for maintenance.

dont have a stand pipe actually I thought making one could make this noise a lot less, its just an internal overflow with a hole in the bottom of the tank, which goes into the ball valve then down a 45 degree section into the sump.

Ah IC. A durso is the easiest type to make and typically pretty quiet.

http://t1.gstatic.com/images?q=tbn:A...l1vyHnIclvcZ8w
http://t2.gstatic.com/images?q=tbn:A...Kpyvz00zuRNPCw

Pretty simple to make but the key is to reduce the pipe size after the standpipe. So If you have a 1.5" Bulkhead in place already you should make a 1.5" Standpipe. Typically you would then drop the pipe size to 1.25" below the bulkhead to the sump however since it's only a 35 gallon and your flow rate is going to be fairly low you should drop it to 1".
If a 1.5" Standpipe won't fit in your overflow a couple bushings in the bulkhead will allot for a smaller standpipe. You could go as small as 1" for the standpipe and 3/4" for the drain line below.

If the durso design is just too big for the overflow no matter what look into a stockman or HGB.

Also just note that you need a 1/8" hole drilled in the top of the cap on the durso standpipe.

hmm good to know, think I will head out to the hardware store or red coral and see what I need for fittngs etc.

Try and fit a 90 that will male socket on one end, this will help with clearance.

went out got 1.5" fittings no way in hell the 1.5" or even a 1" fitting will fit in this overflow which sucks..so now i dunno what to do, i guess look into the stockman and HGB style, anyone have some good info on those?

A street elbow, here is a link to a pic.

http://www.fdsons.com/34x12-cpvc-red...5-p-38134.html

wont fit no way no how.