Benefits of using 2 return outlets?

[ReefSlice]

I'm plumbing my 150's returns, using a fluval sp4, and was wondering why I should use both drilled return outlets vs. just going straight up from the pump in my sump to one return outlet, and capping the other off. My return outlets on the tank are 3/4" while the pump's outlet is 1". I figure by the time I split the lines halfway up, run to two separate reducing 90s 5' apart, and into the bulkheads and loc line, I'll be losing a ton of flow (as well as making the back of the tank a mess with the ghost overflow plumbing already there). I'm debating just going straight up to 1 reducer elbow with 1" flexible PVC, into the bulkhead and 1 locline. Any reason why I shouldn't do this? I plan on having plenty of powerheads so having two points of flow doesn't mean much to me.

 

[HB AL]

Try it and see what difference it Makes.

 

[ReefSlice]

Bump.. plumbing it up tomorrow and want some opinions. I'm leaning towards just using one bulkhead and capping the other, it will save a bunch of room behind the tank and a bunch of headache measuring plumbing. Any reason to use both? I'm guessing I'm going to get 1000gph+- through the bulkhead.

 

[ca1ore]

1,000 through a single 3/4" bulkhead may be a bit optimistic. Fluval SP4 is a good pump but not a head pressure monster. Since you have them, I'd probably use both return bulkheads, just orient the T so that one leg doesn't have a 90 bend.

 

[ReefSlice]

I know I'm going to lose quite a bit due to head pressure and reducing at the bulkhead, which is why I'm hesitant to use both lines. Adding a tee is equal to ~6 feet of head, I can't imagine I'd get any more than 6-700 gph through both after teeing the line off and then turning and reducing at the bulkheads. Am I crazy? Just seems wrong to use such a big pump to get 4x turnover through 2 bulkheads when I can possibly increase that by a lot by just using less plumbing.

 

[ca1ore]

Here's what you do …. run 1" PVC up to a T. Orient the T with the long axis going straight to one bulkhead (thus no 90 degree bend). Continue to run 1" to both bulkheads where you reduce to 3/4". One return will move more water than the other because it has one less turn, but you'll get more total flow than through just a single bulkhead. If your tank actually uses Sch80 3/4" bulkheads you can replace them with Sch40 1" bulkheads because they take the same sized hole.

 

[ReefSlice]

Think I'm gonna do just that... Took me a minute to visualize it but now it makes a lot of sense!