!' instead od 3/4

[JMorris271]

Hi guys.
Newbie here and want to say I appreciate everyone's help with my questions over the last 10 years. There is a treasure trove of knowledge here.

I am trying to set up two salt water tanks now. One is a 75 gal drilled tank that will be a QT with a durso overflow.
The other is to be a 120 gal dual overflow tank using the bean animal overflow.
Concerning the 120 gal tank with 2 1 inch holes and 2 3/4' holes, I want to use the 1" drain as a full siphon instead of the Emergency drain and 3/4 "pipe would be used as an emergency.
I know the status quo is to use the larger pipe as the emergency but I think that the .75" drain' pipe could handle any excess water in an Emergency.
All of this will allow me to use the 1" pipe for the return which I believe is a more desirable size.
Mucho thanks

 

[oscarinw]

I think you are fine to go in that direction. The only case where the smaller emergency drain would be an issue is if you are using close to maximum capacity on your drain and then you get a full-clog. In theory, it could happen. In this case, then your emergency drain might not be enough to handle all the flow. How can you get a full-clog? I think it might have to be a true freak accident such as a bouncy ball getting stuck there or something like that... The way to avoid this risk and still do what you plan, just run a slow return flow and you'll be just fine. Something like 4-5 hundred GPH... That way you know that your emergency drain can easily handle the total flow. However, if your intention is to run a full (or close to) drain, then I'd suggest using the 3/4 as main.