Emergency drain (E drain) should be as big as main drain if not bigger. The purpose of the emergency drain is to handle ALL of the flow of the main drain when it gets completely clogged.
E drain should be complete dry in a true herbie system (where there is no water flowing in it normally, only when the main drain is clogged then water should enter the E drain). So E drain should be higher than your water line.
Tune whatever way you want until the E drain is above the water.
Quote:
Originally Posted by BlueTang<3
So i am helping a buddy do a herbie on his system never have done this before so i have some questions. He has dual overflows, i am going to run a 1.5" bulkhead with a strainer as the syphon line with the gate valve and the 1" on one side as emergency. But he has dual overflows should i have 2 emergency drains with one a little higher than the other or just plug off one of the 1.5 " hole as i am using the other 1" for the return pump. To tune then just open the gate valve all the way and close it till its quite? Drain above or below water line ? The emergency drains just below where water enters overflow or a ways down? Thanks  Should add going to be running a 2000 gph pump or so |