Max flow from 2" inlet?

[Jaws]

I was just wondering what the maximum amount of water a 2" inlet could handle? Reason I'm asking is I'm going to need to pump a lot of water from my sump, some of which will be to the display tank which will have about 15' of head and some of which will be to a frag tank and a refugium which will only be about 4' each of head. I have a hammerhead pump and i'm wondering if I can "T" off the 2" bulkhead in the sump to add another return pump if the hammerhead isn't enough flow for the entire setup. Thoughts?

[Spyd]

You are better off reducing that 2" pipe down to a 1" pipe. 2" will cause a lot of pressure required from the pump to push that much water. Running 2 pumps would cost a lot of money. How big is your display tank? I recently purchased a Water Blaster HY10000 pump. It moves 2600gph of water and is very energy efficient.

[sphelps]

You are better off reducing that 2" pipe down to a 1" pipe. 2" will cause a lot of pressure required from the pump to push that much water. Running 2 pumps would cost a lot of money. How big is your display tank? I recently purchased a Water Blaster HY10000 pump. It moves 2600gph of water and is very energy efficient.

Ahh no that's not correct. Pipe diameter has absolutely nothing to do with static pressure. Static Pressure = Fluid Density * Gravity * Static Height

What is affected is the total head pressure from friction loses however the larger the diameter pipe, the lower the friction losses.

So 2" will have same static head as 1" pipe but 2" pipe will have lower friction losses so using 2" pipe will actually have less total head pressure on the pump and therefore result in more flow than 1" pipe, even if the pump is really small.

As for how much flow a 2" pipe can handle it depends on pump pressure but I'm not aware of any aquarium pump that can exceed the limitations of a 2" line. Consult the RC head loss calculator (http://www.reefcentral.com/index.php/head-loss-calculator) to get a better idea on what you're dealing with.