Looking for caculator for bulkhead size

allincuddy · #1 03-09-2006, 03:14 AM

Well I have a 7/8 inch bulkhead on a 65 gallon tank andit says that size will do 440 gal/hr so that is amax. of 8 turn overs, should be good to go.3 tun overson afrag tank should be good?????
Thanks.

Samw · #2 03-09-2006, 03:17 AM

What is linear overflow size? It says that I need 5" for a 300GPH flow.

mark · #3 03-09-2006, 03:20 AM

Quote:

Originally Posted by Samw

What is linear overflow size? It says that I need 5" for a 300GPH flow.

total measurement of overflow tower (wier).

Samw · #4 03-09-2006, 04:10 AM

So this is the height from the top of overflow to the top of the waterline of the sump right?

TheReefGeek · #5 03-09-2006, 04:27 AM

No, the linear measurement means how long of a distance the water can flow over.

Imagine a waterfall. It is 10 meters across. This is the type of measurement you want.

Now for your overflow, say you have a standard corner overflow, you have two lengths you have to add up for the total linear measurement.

Quote:

It's for drains. So that would probably mean "free flowing".

"Probably" is not a good term in plumging a reef.

Leads to too many floods. That is why this calculator is dangerous. Good as a gernal guide though, a starting point better than nothing.

If you have 20 inches of water in your overflow pushing down on the drain, it is going to flow faster than if you have 5 inches of pressure.

Also you can get some suction/siphoning going, but that is not recommended.

G1GY · #6 03-09-2006, 11:54 PM

Quote:

Originally Posted by TheReefGeek

"Probably" is not a good term in plumging a reef.

Leads to too many floods. That is why this calculator is dangerous.

In your first post in this thread you asked:

Quote:

Is it assuming there is pressure on top of the bulkhead or not?

The correct response from me should have been:
Hell no! There is no pressure on a drain bulkhead! Only the weight of any water that is on top of it.(Weight and pressure are two totaly different things.)

My reply with the word "probably" was just a nice way of saying "No pressure....... Only weight."

BTW, there's nothing wrong with this calculator IMO.

TheReefGeek · #7 03-10-2006, 05:19 AM

Ok, so does the calculator assume there is no weight for the flow rates it spits out then?

I am not a physics expert, sorry if I used the wrong terms.

In my basic knowledge of physics, isn't one of Newton's first laws f = m * a, or force = mass times acceleration? Force is aptly named as N, for Newtons.
And water having mass, being pulled down by gravity at 9.81? m/s squared, will create force. That force when partially blocked at a bulkhead would create pressure, pressure expressed as Newtons per square inch? Maybe there is no pressure right at the bulkhead, just the surrounding glass?

I'm not sure, I just think you can put more through a bulkhead where there is more water sitting on top of the bulkhead than if there is none?

Static · #8 03-09-2006, 07:58 AM

Quote:

Originally Posted by allincuddy

Well I have a 7/8 inch bulkhead on a 65 gallon tank andit says that size will do 440 gal/hr so that is amax. of 8 turn overs, should be good to go.3 tun overson afrag tank should be good?????
Thanks.

Do they make a 7/8" bulkhead? I've never seen any 7/8" pipe. I'm tempted to think you have a 1/2" bulkhead. Is it slip fit or female pipe threads? Remember the size of the bulkhead is actually determined by the pipe that slides/threads into it. And it's the hole inside the pip that's measured, not the outside diameter of the pipe.