How to size a pump to your tank

[yourockit]

Great Thread! Which manufacturers of submerisble powerheads do you most highly recommend?

[jredner]

IITUFFTOBEATII, I'm using that book right now for my Fluid Mechanics class. Haven't read much of it though...

[auratum]

Since one pipe is pressurized and the other is not, the easy way to size the plumbing is to duplicate the size of the pump outlet for that returning to the tank and four times the cross sectional area for the plumbing going to the sump (rule of thumb but again case by case). A pump with a half inch outlet should use half inch plumbing going to the tank and one inch plumbing going to the sump from the tank. A pump with a 3/4 inch output should use 3/4 inch plumbing going to the tank and 1 1/2 inch plumbing going to the sump. Taller tanks can get away with using smaller plumbing going to the sump.

These aren't bad assumptions as long as you buy a decent brand of pump. If you buy a cheap pump and they under-sized the outlet, then your whole system is wacked. I sized many pumping systems in the past for work and got pretty good at associating pipe size to flowrate. I developed my own rules of thumb for what pipe size to use depending on the flowrate. In general - go bigger than you think as it is better to move more water than not enough. Using pipe velocity is a decent way to decide which pipe size to use - 1 to 3 ft/sec is what I would use...

[cali~budfish]

latin doesn't even begin to describe that ridiculously mathmatic post. i'm now cross eyed thank you.

[Pharaoh]

Is it possible to "T" two pumps in to one line and get increased output at a higher head height?

[CHOMPERS]

No, that is akin to parallel electrical circuits (think back to those light bulb experiments from science class).

To use two pumps to get higher water pumping, you would put the two pumps in series and at different heights. In other words, one pump would pump to the other one and that one would take over to pump higher.

If you were able to choose impellers, you could have both pumps on the same level. But that is way beyond the pumps we have access to for aquariums.

[Pharaoh]

Electrical circuits huh?....now I understand, bringing it to an electronic nerds level.

[terrors r us]

I want to know what size of pump to buy. I understand how to do it but
what confuses me is , how much head does my set up have>>
can I say that total head would be ;;
tank height in feet (1foot = 1 head)
each elbow = 1 head
each tee = 1 head
each length of pipe over 20 feet = 1 head
each solenoid = 1 head
each globe valve(if not fully opened) = 1 head


so now I can add all of my heads together and find a pump that
will give me my desired flow rate at so much head.. Is this right????


Example for my tank::::
My tank is 728 gal and I want the water to change over 5 times per hour.
This would need a flow rate of 3640gal/hour.
My piping system has( input and output);;;

8 elbows, 4 tee's, 2 solenoid valves, 20 feet of pipe,5 ft high equals to This is total of 21 feet of head.


These are the spec's of the pump that I was looking at;;
Max head 23feet-----3660gph@17ft head or 7320 gph@3ft head.

Do you think this pump would be a good canidate for my system????


http://koiofdistinction.com/store/view/?id=211&cid=29

[Dr Joe]

Ok, first off terrors r us, it's stated in feet of head not heads .

If your pipe is not undersized for the pump (see manufacturers spec) and is horizontal exclude it. I add elbow, solenoids, spray bars etc to the equation. Plus how high it is from the sump/filter to the top of the tank.

Pumps are spec'd out @ max head as where flow stops (so a relatively useless spec to most people).

The pump you specified may be a little too strong for your situation, the next smaller isn't that much different so check electrical usage and go with the most efficient one.

I hope your documenting your build to share with us .

If you have other questions just start a thread in the appropriate section for a fast response.

Good Luck and keep us posted,

Dr Joe

.

[Toodleypops]

i always just get double the size of my tank