Variable speed/flow return pump?

[der Riff-Konig]

I currently have a 30gl DIY sump system on my 125. The return is plumbed thru a manifold with valves to adjust the amount of flow back to the display tank vs. by-passed back to the sump for longer exposure to the skimming and filtration functions as needed. I want to be able to expose the water to the skimming and filtering functions for extened periods of time, but do it by being able to slow the flow thru the overall process rather than the way it is now, which is going thru the process more times, but rushing thru at max speed caused by the return pumps set speed. If I put a valve right after the return pump to restrict the flow, thus causing resistance against the pump, won't it run hot, raise the temp of the water and diminish the life of the pump? can't seem to find a high rated pump with an external speed controller. FEEDBACK PLEASE?

 

[RichConley]

I've put valves after pumps and never had it cause problems.

Its the same as adding extra head height.

 

[TitansFan]

You can put a valve on the output just not recommended for the input.

 

[der Riff-Konig]

So nobody knows of a variable speed/flow pump manufacturer?

 

[chucksta1]

A/C motors usually run at set speeds. For an A/C motor to function at various speeds (like a ceiling fan with three speeds) is a result of having more than one set of windings. An A/C motor that will tolerate infinately adjustavle voltage is another internal design too.

D/C motors don't care about voltage, less voltage just means less output, but it'd be a Mcguyver operation. You'd need an adjustable A/C to D/C converter and a D/C motor. A return pump is pretty aplication specific, (low heat transfer, low noise and vibration, energy efficient, mainenance free 24/7 operation, etc.) Ithink you'd be hard pressed to find a suitable D/C motor and it would require a stand off pump that's constructed of reef safe materials.

That being said, I'm going to have to delve into the realm of "I don't get it"

I don't think it matters to the skimmer if the water going past it is moving fast or slow, the skimmer takes in whatever water it needs at the appropriate rate and spits it out when it's done with it. Why re-skim it? The speed of water going past the skimmer's intake won't affect the contact time of the water inside the skimmer. The same goes for the filter. Why re filter the water again and again. In my tank, the water goes through a drop filter before it goes into the sump's protien skimmer area. The more of the tank water that goes into it per hour, the more chance it has to get the suspended particulate while it still suspended.

It almost seems like you're trying to get one pump to do two different things. Maybe a "T" from the down pipe with one into the sump and one into a circulating pump (think closed loop) for the manifold, and a really small return pump, would be an easier answer to what you want.

 

[der Riff-Konig]

The thought is, That if the flow going thru the sump, which includes the section where the skimmer is housed, is flowing at 900 gph and the skimmer pump runs at 300gph. Then 2/3 of the water goes into the skimmer area and out and never gets a chance to run thru the skimmer. Thus returning to the display tank "un-skimmed". I am not really concerned with the fuge section or the media area. Its just seems that there are situations where you would want to slow down the gph thru the skimmer section to give time for all the water to have a chance to run thru the skimmer before it is passed on down the line. If a restriction, such as a valve in the retun line does not put un-due stress on the pump then that would suffice. I just thought a speed control on the return pump would be a little more accurate at setting the flow.

 

[Anemonebuff]

Just put a ball or gate vale after the return pump and you can cut flow without damaging the pump.

 

[afishyonados]

I suggest putting a t on the pump with two valves coming off of it. redirect the excess water back into the sump, thereby reducing the back pressure on the pump.
Chucksta1, think of it this way...If protien skimming was like stealing hubcaps, would you want to do it on the highway, or in a parking lot?