1" main siphon, 3/4" emergency drain?

[FluffySackson]

With a pump gph of about 700-760. Possible or reduce flow of pump?

 

[ragin_cajun]

Google "aquarium PVC flow rates". It'll return links to sites with charts showing drain rates of various sizes of PVC pipe. Look at 2-3...that'll tell you "about" what a 3/4 inch pipe will drain.

If the E-drain can drain the pump, I'd do it.

 

[FluffySackson]

Need to reduce flow of pump a bit, thanks.