What size return plumbing?

[kegogut]

Im plumbing my 225 with a 1.5" bean animal. Im purchasing a Jebao DC 12000 return pump. The pump has a 1.5" outlet.

My question is should I have my return plumbing 1.5" or should I reduce it down to get more head pressure? The top of the tank is going to be about 6'.

Thanks for any advice.

 

[ca1ore]

Don't think it really matters one way or the other. Depending upon how you plan to plumb the return (through a bulkhead or over the back) may dictate the answer based on obtrusiveness.

 

[Bent]

I think I'm going to do mine 3/8.

BUT, I could be wrong here, I believe the ratings (head and gph) are based upon plumbing size that comes on the pump itself. Deviations will alter it's performance.

 

[Mrramsey]

The main return line on my pump is 1.5" which runs to the top of the tank then tees off left, center and right all in 1.5". I then reduce it to 3/4 into the tank. So in the end I have 3 3/4 returns.

 

[uncleof6]

I think I'm going to do mine 3/8.

BUT, I could be wrong here, I believe the ratings (head and gph) are based upon plumbing size that comes on the pump itself. Deviations will alter it's performance.

The performance ratings are based on approximations, and do not account for friction loss in the plumbing, either on the outlet side or the inlet side. The flow charts reflect the pump performance based on the total dynamic head which is vertical lift + friction loss converted to vertical lift. This is why the bright shiny new pump rated for 900 gph @ 6', is only putting out 300 gph at 6'. (Some pumps are worse than others, so just an illustration.) You are right, deviations will alter it's performance. The larger the pipe, the higher the output.

The size of the inlet and outlet of the pump, do not determine the size of the plumbing.

 

[Bent]

The performance ratings are based on approximations, and do not account for friction loss in the plumbing, either on the outlet side or the inlet side. The flow charts reflect the pump performance based on the total dynamic head which is vertical lift + friction loss converted to vertical lift. This is why the bright shiny new pump rated for 900 gph @ 6', is only putting out 300 gph at 6'. (Some pumps are worse than others, so just an illustration.) You are right, deviations will alter it's performance. The larger the pipe, the higher the output.

The size of the inlet and outlet of the pump, do not determine the size of the plumbing.

:thumbsup:

Good to know.

 

[uncleof6]

Im plumbing my 225 with a 1.5" bean animal. Im purchasing a Jebao DC 12000 return pump. The pump has a 1.5" outlet.

My question is should I have my return plumbing 1.5" or should I reduce it down to get more head pressure? The top of the tank is going to be about 6'.

Thanks for any advice.

No, you do not want to reduce the size of the pipe to get more head pressure. Head pressure reduces the output of the pump. High pressure = low volume, and low pressure = high volume. Centrifugal pumps, even pressure biased pumps, perform best at low pressure. Pressure is rather ambiguous, because there are many different ways to express it in this context. It is easier to understand in terms of friction loss, which is based on velocity, viscosity, inside cross-sectional area of the pipe, and a couple other things, of less significance. Roughly it translates into pressure, however static lift also translates into pressure, so....some folks mix up pressure and weight...

Friction loss calcs show that at a given static lift, the larger the pipe, the more volume the pump will output. Since what we want is volume, always increase the size of the pump, never reduce it. Friction loss is based on velocity, (flow rate) so friction loss calcs can answer the age old question of "what pump should I use." At a given static height, given plumbing configuration, given flow rate, the calcs can tell you what the pump needs to be able to do to reach the given flow rate, resulting in the pump needs to be able to put out X gph @ Y' dynamic head, which fits nicely against the flow curves.

The best return system runs "straight up" without reducing in size, or using gadgets that increase "pressure," which means up over the back of the tank, terminating with a 45° outletting just below the water surface. Loc-line, penductors, eductors, oscillating gadgets, there is no end to the ways marketers will try to get your money—all serve to increase pressure at the sacrifice of volume, under the guise of distribution, which is wholly the job of the power heads, not the return system.