Do I need a valve on sump plumbing?????

[windcoast reefs]

Okay, well thats a consideration. I can always add the valve later if I need to i guess.

[sphelps]

A valve on the return line for sure but not the drain unless you have two drain pipes in a herbie configuration.

Your drain size is fine

[mark]

with an external return pump handy a valve/union on both sides for servicing

[monocus]

i would probably go with a bigger drain.i'm using a stockman with a 2" drain

[sphelps]

Originally Posted by monocus

i would probably go with a bigger drain.i'm using a stockman with a 2" drain

I'm not sure how easy it would be to change out a 1" bulkhead to a 2" bulkhead, you would have to redrill the hole and even then there will not likely be enough clearance for a 2" bulkhead in the overflow box of a 50 gallon tank. a 1" drain will run up to 700 gph without an issue, and more than likely this is not the actual flow rate it will receive.

windcoast, what pump are you using or plan on using?

[lorenz0]

I have a gate on my drain, nothing on my emergency just it gets plugged. On the return I am running a check valve, which I reccomend. In 3 years I have not had anything overflow with this set up.

On my cube I had ball valves on the return and drain... no check valve. Now this set up I Had a spill once which fried a powerbar. everytime I did a water change I had to close the return line, there were a few times I almost forgot.

[Blom]

The flow though a gravity fed drainage line that discharges to atmospheric pressure can be roughly calculated using the continuity equation as it is a product of flow velocity and cross sectional area.

Q = A * V

Where Q is flow rate, A is cross sectional area of the pipe, and V is velocity.

The units work out this way:

M^3/sec = M^2 * M/Sec
OR
Ft^3/sec = Ft^2 * Ft/Sec

You can almost neglect head pressure as this will be offset by frictional losses in the pipe.

Remember you need to switch your time units from sec to minutes and convert to Gallons to get you gpm rate.

A good article for this can be found here:
http://www.agf.gov.bc.ca/resmgmt/pub...s/590304-5.pdf

Hope this helps.

[bignose]

You could also put a valve after the return pump to control flow rates if you don't want one on the drain.

[windcoast reefs]

Originally Posted by sphelps

I'm not sure how easy it would be to change out a 1" bulkhead to a 2" bulkhead, you would have to redrill the hole and even then there will not likely be enough clearance for a 2" bulkhead in the overflow box of a 50 gallon tank. a 1" drain will run up to 700 gph without an issue, and more than likely this is not the actual flow rate it will receive.

windcoast, what pump are you using or plan on using?

Hey! Im using a Hydor seltz pump (800 gph model). I calculated the loss in the gph from the head and it equals out to about 500 gph.

[windcoast reefs]

Originally Posted by monocus

i would probably go with a bigger drain.i'm using a stockman with a 2" drain

Thats pretty much impossible for me to do. I already have the largest bulkhead that I can get for the hole. And I can't drill it out anymore without affecting the structure of the tank.

I can maybe step up to a larger pipe ( 1 1/4" or 1 1/2"), but I don't know if it is a benifit considering the bulkhead restricts the flow.