Overflow box issues

I had a similar problem when I upgraded my return pump. My overflow is an Ehopps rated to 300gph and my return pump is right around 300-320gph at the height of return. I solved my problem with a T and ball valve off the discharge line.

I was surprised to read that the T method was a bad way of solving the problem. I have always heard that a ball valve in line with the return hose can damage the return pump? I haven't noticed any increases in water temperature and I only have 30g DT with a 10g sump so im not too concerned about power used but it is interesting for future knowledge when I want to ramp up my setup. I might even fix my setup right now if you're sure about this...

AZDesertRat did you learn this from your own experience or something you heard somewhere else like me?

 

I believe the answer is in the second sentence and is very clear, simple and to the point. Install a ball valve on the discharge and throttle the return flow, it does not get much simpler than that and is proven time and again. Valving or restricting an overflow is a disaster waiting to happen and returning flow to the sump is a waste of energy and money, again proven time and again and easily demonstrated for those who doubt what I am saying. Pumps and pumping systems have been my life for 37 years and I don't join in forums I have no knowledge about unless I am asking for advice myself.

 

If this was the case then putting a T and then a ball valve on that, like you mentioned you did, does the same exact thing, it's restricting the flow from the pump. Like I said, it never caused me any issues and I believe that this is one of those, "I heard from him and he heard from her" type things. Mine worked great.

Karma for DesertRat

 

Throttling a valve does not harm it at all. In fact as AZ said, it will prolong its life. I have installed many, many valves at work, including large pumps at nuclear power plants, Some 24" and larger in diameter on the discharge, and they are always followed by a valve to throttle the flow. ALWAYS.

 

Many municipal water utilities used to install pressure relief valves on their booster pump systems in the old days when power was cheap. The problem is your pump is producing 320 or whatever GPH when all it really needs is 200 GPH so drawing the wattage to produce that larger amount. The pump is actually working harder, drawing more power since it is pumping more water and is producing more heat. To understand what I am talking about you need to understand two principles or hydraulic theory, Bernoulis Law and the Laws of Affinity. Both have to do with centrifugal pumps and how they operate.
Basically what it amounts to is a centrifugal pump can actually become more efficient when you add head to the pump via additional head. Additional head can be added via a restriction on the return such as smaller diameter piping. fittings, valves, additional height or any combination of the above. It could even be accomplished by lowering the speed of the pump but for our uses that is not an option. Additional head in no way hurts the pump since it is actually doing LESS work so can even extend its life.
Returning flow to the sump does just the opposite. The pump is stil producing the maximum flow, you are just returning it to the sump or wasting energy. Since it is doing maximum flow, it is drawing maximum wattage and producing maximum heat since they are related..

Its hard to grasp but read up on Bernoulis Law and The Laws of Affinity if you are bored and you will understand better. A Kill A Watt meter can be had at Lowes or HD fo less than $25 and is a really good tool for making an aquarium more efficient, I have cut my power bills by over $100 a month this past year by monitoring my power usage and changing some of my equipment and usage patterns.

 

***I am not arguing that putting a ball valve on the over flow is good idea because I agree that that is not a good idea at all***

Just asking because I am new. It doesnt make sense to me that the pump would be over working by recirculating water back into the sump.. I see that the pump uses an alotted amount of power and if I redirect some of the return flow back into the sump it will increase the amount if time to return water to the DT thus lowering the rate/flow of the return and regulating my over flow in the system.

Basically the T method makes the return pump take twice as long to work but places no mechanical strain on the return pump.

By placing a ball valve directly in line with the return line (and having no return flow to the sump) then I will be adding mechanical stress to the return pump and making it work harder and probably increase water temperature from residual heat from the motor. The inline ball valve is like a wall the return pump will have to push through where as the T method just takes longer for the same volume of water to circulate.

Work = Force x Time

The work should be the same in both of our methods except that using your method will lead to a shorter life of the pump do to an increase on the force/stress you added with the inline ball valve. By using the T method you will increase the life of your pump and lower the force exerted on its motor... IMO

The pump is going to pump the same regardless as far as I understand it and limiting that with an inline ball valve is more dangerous to the return pump than returning water to the sump with a T IMO.

 

His reply wasn't directed towards you I am 99.9% sure it was towards the person on the first page of the thread.

 

Touche. I am definitely not as well read on Bernoulis Law and The Laws of Affinity. I am definitely going to read up on that and will be replacing my T valve after Christmas break. Thanks 8)

 

No, its the opposite, flow equals work. Restricting flow creates less work the pump must do so consumes less wattage and produces less heat. Like I said, its hard to grasp but its has to do with centrifugal force and not a positive displacement pump which is a whole different story we are not dealing with here. Trust me it works!

Look at any particular pump curve. Look at the shutoff head or height it will pump then move across the curve to the watts or amps it draws as the head increases, the power consumption goes down not up which means it is doing less work, creating less heat and the pump will last longer. I have sold, installed, troubleshot and serviced pumps for 37 years, I wouldn't lie to you.

 

I think you're getting there. Just you'll have to look at how a centrifugal pump works. You're almost there, just a little hung up on restricting the pump is making it do more work. I can see how it makes sense, but that it is not the case. AZ described it well and I'm not sure I can further his explanation any better right now.

I know that my marineland return for example can actually be dialled down, albeit slightly, right at the pump. This is like that from the factory and is essentially the same as a valve on the return line to throttle the pump. I know they wouldn't do it if it was "bad" for the pump .

Wish I could explain it further for you, but I'm drawing a blank, been a while since trade school lol.