Intresting flow question

Canadian Man · #1 05-08-2003, 01:07 AM

So let's say you have a powerhead like a MJ 1200.
Position it in a tank. Now when the powerhead is running, would it not make sense to count the flow comming out of the output nozzel as well as the flow comming through the intake?

This is probably a bad example and a better one may be a standard sump set up on a tank. The return is 600gph and the flow going into the overlfow box is 600 gph.. should the intake count for anything?

I realize that it's not as focused as the output of a pump but it is current and it should count for something. If you have 1000gph comming out of a pump you also have 1000gph going into the pump. RIGHT?

Let's hear your thoughts

StirCrazy · #2 05-08-2003, 01:11 AM

I am not sure I get where you are going with this? do you mean to count it in overall tank flow or what?

Steve

Aquattro · #3 05-08-2003, 01:22 AM

Jon, I don't think you can count the flow going into the pump. Even on the stream, there is very little water movement until it gets within 1/4" of the intake. In a ratio of water movement out compared to in, the in would become insignificant.
To get an idea of the flow, drop some spirulina flake near the bottom of the PH....it won't do much until it's almost in the pump.

Canadian Man · #4 05-08-2003, 01:34 AM

Not really going anywhere with it just something I was thinking about

So Big fat NO?

Aquattro · #5 05-08-2003, 01:39 AM

Quote:

Originally Posted by Canadian Man

So Big fat NO?

Right.......BFN

trilinearmipmap · #6 05-08-2003, 02:12 AM

On a related note...

1. There was some recent reef central discussion on eductors, essentially a pump forces water into a tapering nozzle, the increase in flow velocity through the tapered nozzle brings in water from the sides much like a venturi works. I am wondering if anyone has tried adding a small eductor onto a powerhead.

2. I wonder whether flow would be better if, rather than just a powerhead, the intake of the powerhead was from some pipe/tubing 2 or 3 feet long, besides just flow from the powerhead would this not add to overall tank circulation by moving water from point A to point B better?

Aquattro · #7 05-08-2003, 02:41 AM

Re; the eductor, no, it hasn't been used over a powerhead. It requires a MAG 18 minimum to rn the thing. However, if you had the pump already, the compact eductors were only about $25 US

StirCrazy · #8 05-08-2003, 03:10 AM

Hmm after reading this a couple times I realized what you were getting at

slow day today hehe..

anyways think of it as a pump "moves" a specific amount of water.. so a magdrive 12 will move 1200gph (in ideal conditions).

hmm I better stop befor I confuse myself here

I know what you mean but I also say no.

Steve

Canadian Man · #9 05-08-2003, 03:11 AM

Quote:

Originally Posted by StirCrazy

Hmm after reading this a couple times I realized what you were getting at

slow day today hehe..

anyways think of it as a pump "moves" a specific amount of water.. so a magdrive 12 will move 1200gph (in ideal conditions).

hmm I better stop befor I confuse myself here

I know what you mean but I also say no.

Steve

I thought you of all people would agree with me Steve

Canadian Man · #10 05-08-2003, 03:13 AM

Although if the pump was big enough and the aquarium was small enough then the intake would actually account for something.
Let's say a 10g aquarium with a mag 12! the intake woudl in that case actually act as a some flow increase because of the small watervolume.

You guys are thinking on too large of a scale