300DD Herbie Overflow

ohioboy706 · Dec 8, 2017

Im setting up a 300DD and am thinking about just running 4 drains on it and bringing the return over the back. Wanted to see what everyone thought. Its a standard 300dd with 1 inch drains and 3/4 inch returns. I want to run 3/4 inch returns as primary standpipe opened under tank to 1.5'' drains with a gate valve on each. 1'' emergency drains lines would be opened after bulkhead to 2'' lines that would all go to a 150 gallon stock tank filled with live rock. From the stock tank it would go to a custom built sump. I will run the return line over the back and it will be a 1'' return. This will be a sps dominated tank and wanted to hear opinions, advice or whatever.

Ashish Patel · Dec 8, 2017

I don't see anything wrong with what you are doing but how much flow do you want to run? How large are the bulk head drains on the 300DD - You mentioned 1, 1.5" and 2".? If the holes are 1.5" for the drains and your using the holes which are for the returns I would say you have more than enough drainage power. I was concerned I would have an issue with flow with 2X1" drains on my tank which is 130 gallon system so I made a 1.5 emergency drain. However, I can easily push 1800 gallons/per hour flow with these 2x1" drains and the emergency drain is never used. The full siphon seems to move water much more faster than my older systems with standard drains filled with air. Good luck

ohioboy706 · Dec 8, 2017

the tank has 3/4'' return that i am going to make 1.5 drains after bulkhead as my full siphon. Then it has 1'' bulkheads that i am going to make im going to make 2'' after bulkhead. Nice setup by the way

Ashish Patel · Dec 8, 2017

Thanks..

You do realize a 3/4" drain can't be coverted to a 1.5" drain! Since the entire watervolume will condense into a 3/4 area which will restrict flow along the entire drain. Thing of a ball valve on a 1.5" drain. If its turned half way you have max flow at 1/2 the pipe diameter.