Unique Pump Recommendation Needed

[hahnmeister]

With any closed loop, the head is 0. The pressure that the water has going into the loop is the same as the water coming out (that is when the pump is off). Otherwise, even when the pump is off, you would have water flowing. Think of it this way, its sealed, so what goes down, must come up.

 

[scolley]

Thanks hahnmeister for that clarification. That simplifies this a LOT. And really boosts the ability of any pump to handle this. Taking that 5 feet off the requirement really helps!

All my plumbing parts came in last nite, so very soon I can run a test with the OceanRunner 3500. It will be a hoot if it turns out I don't even have to upgrade to the big stuff that has been suggested here.

Will see soon. Thanks.

 

[scolley]

Just wanted to say thanks to everyone that helped me out here... Thanks!

I spent a great deal of time with the spreadsheet from which the Head Loss Calculator here is derived. I had to modify it a bit - my tank is NOT SW but fresh, so that changed a value or two. But ultimately I got a great usable tool out of it.

Many of the pumps recommended here could take me to the flow rates I was looking for. But what I DID NOT know is that I had to scale my flow rate expectations back if I was not going to exceed 4 ft/sec, and aparently critical flow rate - where after that most of you engery is getting chewed up with friction (for water flowing through PVC).

That lead me to settling on a Velocity (Sequence) T1. And I gotta tell you, that's one great little pump!

It does contribute a little heat, but not too bad as far as I can tell.

And silent as a STONE! Just what I wanted.

I'm only getting a measured 360 gph. And the spreadsheet predicts about 450. So, I'm still shy of where I need to be. But for the price of this little pump, and this SILENCE that it operates in, I'd happily pick up another and run an additional, separate closed loop, to pick up a bit more filtration.

Thanks again for the help!

 

[jdieck]

<a href=showthread.php?s=&postid=9739577#post9739577 target=_blank>Originally posted</a> by scolley
Or NOT for the Eheims.

It appears that max head pressure is 4 meters. And it appears I'm ways beyond that. And even if it would blow though that pressure, it would apparently be at a trickle. I think Eheims are out.

Which gets me back to the original recommendation. Question is, I suppose, is which is the quietest?

Heat is less of a problem, as long as it doesn't raise the water temp much more than 4-6 degrees.

First what is your head pressure? You say a lot but how much is a lot?
First if it is a closed loop (from the tank to the pump and from pump back to the tank the 5 feet height should not be accounted for as part of the head pressure (the same 5 feet will be in the inlet than oin the outlet so net head pressure due to height is zero.
Second try using the head loss calculator to determine the head loss at 600 gal/hr, it does not matter which pump it is calculation wise it is only important that you select a pump that can give you the 600 gal/hr.
Enter your piping data as required (for height enter 0) then switch between different pumps until the result is 600 gph, then read the head pressure drop at that flow. Now you know your actual estimated head pressure due to the flow velocity and can select a pump using the pump curves to determine it's capacity at the found head.
Unfortunately, high head dinamic pressure require pressure rated pumps (Iwaki like) and pressure rated pumps = higher noise level due to required higher RPM to overcome the drop.
An example Iwaky 30 RXT will give you 600 gph at 9.5 feet. An Iwaki 40 RXT will give you 600 gph at 12.5 feet, an Iwaki 55 RT will give you 600 gph at 18 feet and an Iwaki 70 RT will give you 600 gph at 25 feet.

Here is the link to the head loss calculator:
http://reefcentral.com/calc/hlc2.php

In this link there is a list of the most popular aquarium pumps, scroll down, for a particular pump click on the more information and it will show you the pump performance curve.
http://www.reefs.org/library/pumps/

 

[marcrunner]

i agree that eheim pumps are great. I think that they are very fragile and toy like though. I think that you should also check out Gorman Rupp pumps. Very quiet, durable, and if something breaks or fails, they have great customer service and all parts are replaceable. I have an OR3500 that I used the wrong pvc cement on the output, and since it is built into the housing, I am pretty sure the whole pump is garbage.