Drain plumbing question

[Biff0rz]

I'm setting up a used reef ready tank. The overflow has a Herbie style drain with two standpipes and the diameter is 1.25" each on the dry side past where the bulkhead is. I plan to add a true union ball valve on the main drain (nothing on the emergency). I think I read somewhere that the drainpipe should expand 1/4" larger. Thus, I should be buying 1.5" drain piping and a slip x slip reducer (flip to expand), right?

So I was going to buy-

• 1x 1.25" ball valve
• 2x Schedule 80 reducing coupler 1.5" slip X 1.25" slip
• 2x 46" 1.25" Schedule 40 piping
• 2x unions
• 4x elbows
• 4x 90's

Or, did I read something wrong and I should just be buying 1.25" parts?

 

[Ron Reefman]

IMHO you are OK with the 1.25" plumbing. Going a 1/4" bigger isn't really going to make much difference unless there are more than 1 or 2 elbows on the way to the sump. Then going bigger could be useful.

 

[mfinn]

I see no reason to go larger than the 1-1/4" you have now.

 

[Biff0rz]

I see no reason to go larger than the 1-1/4" you have now.

Yea so I am routing to a fish room, I'm aiming to do it with 45's, maybe one 90. Reading on gmacreef under the herbie notes, it says to expand the pipe if possible. That's why I'm asking.