Beckett pump selection

[jackalcleo]

For beckett pump selection which is more important?

The pressure rating of the pump or high flowrate? Eg like MD55 is pressure rated but only 3000++L/hr compare to Rio32HF not pressure rated but high flow of 7000++L/hr.

[CalciumReef]

A pump that is not pressure Rated will encounter back pressure due to restriction of flow at the beckett nozzle.In the long term, there is a tendency to break down.But for pressure Rated pump, it will deliver almost consistent flow rate thou it encounters flow restriction at the beckett nozzle.I believe the higher flowrate pump will deliver about the same amount of water or slightly higher compared to the pressure Rated pump after minus away head loss and restrictions in flow. Go for pressure rated IMO

[dandelion76]

For beckett pump selection which is more important?

The pressure rating of the pump or high flowrate? Eg like MD55 is pressure rated but only 3000++L/hr compare to Rio32HF not pressure rated but high flow of 7000++L/hr.

Go for pressure rated pump as it will give you much higher flowrate when there's huge pressure lost in your application.

Let me recall this example:

RIO 32HF 8000 l/h Pressure Head: 4.3 m

Resun MD55 3000++ l/h Pressure Head: ~ 8 m

In the first case, let say there's a pressure lost of 1.8 m (due to height, bends, frictions etc.) RIO 32HF will give u 4940 l/h and MD55 would probably give u close to 3000 l/h.

So in this case RIO 32HF produce higher flowrate.

But now say due to the same situation but with beckett nozzle the head lost is 4.3 m (just an extreme example here for illustration), what's the flowrate of RIO32HF?

0 l/h !!

As RIO 32HF generated pressure head is totally lost (to back-pressure), but in this case MD55 (or any pressure rated pump) will probably gives u more than half of its rated flowrate, which is still above 1500 l/h (the relationship of flowrate vs. pressure lost is not linear, so normally the figure will easily surpass 1500 l/h).

So that's why many avocates to use non-pressure rated pump for low head lost application (i.e as return pump) but pressure rated pump to drive beckett skimmer or to return water to tank that's way high up (ie. from sump in basement to the main tank in living room, ang moh like to do this )

Happy reefing..

[blueheaven]

Can a Rio 32HF be used to power a 1 feet high, 6 inch diameter beckett?

Because I think that the build and height do affect pump selection too

[jackalcleo]

As RIO 32HF generated pressure head is totally lost (to back-pressure), but in this case MD55 (or any pressure rated pump) will probably gives u more than half of its rated flowrate, which is still above 1500 l/h (the relationship of flowrate vs. pressure lost is not linear, so normally the figure will easily surpass 1500 l/h).

Happy reefing..

Is 1500L/hr the min require amount of flow to go through the beckett nozzle?

[dandelion76]

Is 1500L/hr the min require amount of flow to go through the beckett nozzle?

Not really, the above example is just meant for explanation. Do remember I am not an expert of any kind but just trying to explain what I understand ... to put it short, just remember these principles:

Generally all venturi nozzle converge fluid flow (air or water) through venturi nozzle (this is true for beckett nozzle too). As the flow is converge towards the centre of the nozzle which has a smaller diameter the speed of the flow is increase markedly (with the same flow rate, just imagine same amount of water flow through two different pipes, big one at slow speed, small one at much higher speed). This increase in speed create a low pressure region, hence if there's an opening around this region, external fluid at higher pressure (atmospheric pressure for air) will be sucked in.

In addition,

1. Beckett Nozzle create a significant pressure drop when a stream of fluid flow through it.

2. For beckett nozzle to suck in more air, higher flowrate THROUGH the nozzle is required.

3. To supply higher flowrate, a higher pressure rated pump is needed (so after the pressure drop within the nozzle there's still a lot of pressure left, and this will translate into hgiher flowrate through the beckett nozzle, more air will be suck in, after exiting the nozzle due to pressure change some complicated physical transformation will take place and many many micro bubbles will form as a result).

So, base on the above few principles, one can easily see that in order for beckett nozzle to suck in more air (for skimming), one need the ensure there's sufficient water flow rate through the nozzle.

In order to supply higher water flow rate, one need to employ a pressure rated pump (preferably) that can supply water with higher pressure head as it is more efficient for this kind of application. Non-pressure rated pump can still be used if it has sufficiently high pressure head, but this will not be as effective as compared to pressure rated pump and the performance of the beckett skimmer is somehow compromized.

Of course, the selection of pumps will be based on running cost as well, so there's always trade-offs between running cost and skimmer performance, and this is where all the confusion/debates originated.

Hope this help...

Cheers.

[dandelion76]

Can a Rio 32HF be used to power a 1 feet high, 6 inch diameter beckett?

Because I think that the build and height do affect pump selection too

Bro Blueheaven, I think for ur case I'd advise u to use MD40(or RIO 20HF, both none-pressure rated). For ur skimmer spec it looks okay even if u run it with RIO 20HF, many reefers have good result running their mini beckett using RIO 20 (put in-sump).

I ran my 24" Beckett with 8" chamber using Rio 20HF before, can skim but the results is of no match to that produce using MD55 (current set-up).

In addition, dumping so much heat in ur tank water using RIO32 HF (unless u use it externally, but some ppl say.. ) wil increase ur chiller load and at the end of the day increase ur overall running cost still.

[jackalcleo]

Bro Blueheaven, I think for ur case I'd advise u to use MD40(or RIO 20HF, both none-pressure rated). For ur skimmer spec it looks okay even if u run it with RIO 20HF, many reefers have good result running their mini beckett using RIO 20 (put in-sump).

I ran my 24" Beckett with 8" chamber using Rio 20HF before, can skim but the results is of no match to that produce using MD55 (current set-up).

In addition, dumping so much heat in ur tank water using RIO32 HF (unless u use it externally, but some ppl say.. ) wil increase ur chiller load and at the end of the day increase ur overall running cost still.

if you are using MD55 for your 24" already then my 32" need to be at least same or better

[blueheaven]

Bro Blueheaven, I think for ur case I'd advise u to use MD40(or RIO 20HF, both none-pressure rated). For ur skimmer spec it looks okay even if u run it with RIO 20HF, many reefers have good result running their mini beckett using RIO 20 (put in-sump).

I ran my 24" Beckett with 8" chamber using Rio 20HF before, can skim but the results is of no match to that produce using MD55 (current set-up).

In addition, dumping so much heat in ur tank water using RIO32 HF (unless u use it externally, but some ppl say.. ) wil increase ur chiller load and at the end of the day increase ur overall running cost still.

Thanks bro dandelion

I am actually thinking of adding an extension chamber and run it on a MD55

Your explaination about the flowthrough to the nozzle is suberb!!!

[dandelion76]

No problem bro. Am just trying to share what I understand..

Btw, do remember that there's always a limit on how much water could flow through a pipe with a given diameter, as the flow will get CHOKED when it reach the maximum flowrate limit (as water is incompressible).

So though generally for pumps available to hobbyist we generally see improve performance when higher pressure rated pump is used, but its not always true that the higher the pressure the better hor..