determining the correct size pump?

[bluehd60]

how do you determine what size pump you should use for your system?

[Greg Hiller]

heh, sorry to give you a flippant answer, but you come to the BRS meeting early next year when Matt L. gives his plumbing lecture again to the club. :D The date's not set yet.

[Jocko]

But what if I want to pick out a pump now and put it on my christmas list?!?!

[steevareno]

How big is your tank? Are you going to run it inline or in sump? Is it returning back into a closed loop?

[Jocko]

I don't want to highjack the thread, so I won't post my details. But I'll stimulate the conversation a bit. Are there strong pro's or con's for either of the two usual approaches?

1. Really strong pump. 10x or more turnover. Main source of circulation in tank.
2. Medium strength pump. Much less turnover. Circulation supplemented by powerheads.

[ReeferDude]

take how big tank aand the sump and then add them and then take that n umber and you want top circulate that 4 times in an hour for more power just keep adding

[besl]

bluehd60 - what I did initially on my set up - after reading countless posts, I "learned that I needed to move 3 - 5 x turnover through the sump - so that's what I did. When I saw that my in-sump ER skimmer was not perfroming I went back to Message Board University and took an advance post reading course that explained that the sump throughput should match the skimmer pumps flow rate. So I throttled back the return pump for this lesser flow and voila, my ER skimmer that got wonderful reviews redeemed itself and works wonderfully. Wondering what the 3 - 5x turnover rate through the sump was all about I went back to the posts and learned that this "rule of thumb" is right up there with 5 - 10x guidance on lighting and 10 - 20x flow in the display - rough guidelines that work in some tanks but not others. So, if you want your in-sump skimmer to work efficently then it appears you should match the return pump flow rate (e.g. sump turnover) to the skimmer pump flow rate... if you want to maximize circulation in your display using the return pump and have less relaince on powerheads then go with the 3 - 5x rule of thumb... JMHO though.

[JayM]

It costs a heck of a lot less (in energy) to move water vertically with a powerhead than horizontally (head loss) from a return pump. As echoed above, there is a point of diminishing returns with turnover in a sump/refugium.

My AGA overflows max out at 400 600GPH, and I don't run either at the absolute max flow to account for potential biofilm, etc losses in the drains.
I supplement with tunze nanostreams, modded to do about 1000GPH each. I'll spend 8 watts to do 1000GPH of flow......

[nanoguy1210]

Most reef tanks you want to see atleast a 10 time per hour turn over. If you are worried about a pump being to much you could always run an inline ball valve to regulate the flow.

[Liam]

Most reef tanks you want to see atleast a 10 time per hour turn over. If you are worried about a pump being to much you could always run an inline ball valve to regulate the flow.

the 10x turnover rule is kinda old methodlogy IMO.
I have Used various flow rates in the past.High flow rates = high electrical cost,noise,bubbles and are not needed IME.
If you have a sump and a skimmer i would calculate your flow rate to match the amount of water your skimmer processes in gph.
Like others stated,you are best off using other methods such as power heads or a closed loop with an efficient non pressure rated pump to obtain flow.Using a return as a primary means of creating flow is just not efficient.

[garyl]

Some things to keep in mind.

I used two smaller 600 gph pumps on my 180. I think it gives a little redundancy in case one craps out. I also keep just one of them plugged into an UPS in case of a power outage.

When electricity started to rise I cut one of them off to save money. Big mistake. Within a month I noticed that my tank started to suffer from the decreased turnover (and maybe less oxygen). I turned both pumps back on and the problem went away.

To keep up with the preceding comments. I have a 55 gal sump with an Aqua C EV240 on a 800gph pump. With the back pressure it probably pumps about 600 gph.

HTH,

Gary

[Liam]

Some things to keep in mind.

I used two smaller 600 gph pumps on my 180. I think it gives a little redundancy in case one craps out. I also keep just one of them plugged into an UPS in case of a power outage.

When electricity started to rise I cut one of them off to save money. Big mistake. Within a month I noticed that my tank started to suffer from the decreased turnover (and maybe less oxygen). I turned both pumps back on and the problem went away.

To keep up with the preceding comments. I have a 55 gal sump with an Aqua C EV240 on a 800gph pump. With the back pressure it probably pumps about 600 gph.

HTH,

Gary

good point on the two pumps,always the way to go if possible

[S Hunter]

http://www.advancedaquarist.com/2007/5/aafeature2#h1

you can look here, it may help, install the Pump Head Loss Calculator and play around with it :)

[MikeG]

I agree with what most have said here. For a return pump, try top move about the same as your skimmer. Any more and you are just turning over water and a return pump is the least efficient way to do it. Again powerheads or a closed loop is what you want here for in tank flow.

Total flow in the tank is very variable depending on the type of pumps, what you keep and the size/shape of the aquarium. You Ideally want very wide flow patters like you get with many of the propellar style powerheads. You also want random flow achieved through wave makers, controllers, or devices like Oceans Motions.