Overflow and return question

[m0nk3y69d]

I have a eshopps pf300 overflow and a mag 9.5 return with a cable to control flow and I am having a hard time gitting the flow to where it equips out either the lvl in my sump wile raise or the lvl in my tank will raise how can I equal this out I have Ben trying for 2 days now

 

[EFSleeper]

I have the same overflow on my 125. The easiest way is to order another U tube. I'm running 2 on it and I'm pushing 1280 gph through my sump. Pump is maxed out and still have an air bubble in 1 of the U tube, so I know it would handle more. Other than that only way is to just keep dialing it in until you hit a spot you are happy with. That is the problem with hob overflows, it's hard to get them where you want with your pump unless you figure out a way to just max your pump out, But with that if your suction fails just a bit you risk flooding your display

 

[m0nk3y69d]

I was just thinking about drilling it and installing an overflow but I don't want want to crake the tank

 

[Reef head]

The water has to be pumped up and there will be a loss in the sump to fill the pipe and to create the overflow. Draw a line of operation point at the sump so that when the pump is turned off that you don't overflow the sump. It is a very simple process, what goes up... Should come down.

 

[vlangel]

I was just thinking about drilling it and installing an overflow but I don't want want to crake the tank

You can drill the U tube and attach airline tubing to it. Attach the other end of the air line tubing to an aqualifter pump intake. Then attach a second piece of airline tubing to the output of the aqualifter and run it into the back of the overflow. That way the aqualifter sucks until a syphon is started every time the pump turns on. I use this method and it works great. I have pics if you need to see what I am talking about.

 

[Reef head]

Have you looked into a cpr overflow?

 

[m0nk3y69d]

No not really I will have to check them out

 

[m0nk3y69d]

Would gitting a bigger overflow help say 1200 gph witch I know my pump won't pump that much

 

[Reef head]

Correct. You larger return than what your pump is. I run the c's 90 for 2 years now with great success. The only thing is you need to replace the pre filter for the aqua lifter pump. I also installed a check valve to not allow for air to draw in once pump is shut off

 

[m0nk3y69d]

I think I might get a internal overflow for 1200 gph and drill my tank and pray for the best but schould I use a 1 inch bulkhead like I am now that way I wouldent have to replace all of my pluming or schould I go bigger

 

[Reefing Madness]

Your overflow is rated at 300gph, your pump after 3' of head loss is rated at 740gph. What you need to do is branch off the return line back to the DT, install a T pvc in the line, with that line running back to the Sump, at the end of that pipe, install a gate valve. This will allow you to fine tune adjust the water going back to the DT so that all stays level. You only want 300gph or less going back to the DT, you could get a smaller pump or install the T line.
http://www.melevsreef.com/allmysumps.html

 

[AZDesertRat]

NO! NO! No!
Installing a tee and valve to return flow to the sump is a very antiquated, extremely inefficient way to lessen the flow and leads to heat issues, noise and higher power consumption.

Instead, install a ball valve in the discharge line of the pump leading back up to the display tank. This is PROVEN and DOCUMENTED to reduce power consumption, lower heat gain and almost always makes centrifugal pumps more efficient. I hate t when someone talks about returning flow to the sump as it is a waste of energy and harder on the pump by far. This concept is extremely easy to prove with a simple $20 Kill A Watt meter and is documented and proven in Bernoulli's Theory and The Laws of Affinity which are both basic hydraulics and engineering concepts.

I will argue with Marc on this one as he is completely of base there. I do love his site and his explanations of how a sump works other than a few mistakes and recommend it often.

In your case the overflow box is grossly undersized compared to the pump and I would recommend a larger overflow box or a smaller pump better matched to the overflow after headloss is calculated in. Again try a Kill A Watt meter and see what I am saying is true and sound advice. Pumps and water systems have been my profession for 39 years.

 

[Reefing Madness]

Call it what you will AZ, there are more than one way to skin a cat, and also, it does work still, even in this day and age.

 

[AZDesertRat]

Working and being efficient are two entirely different things. Spend the $20 and get a meter or you are welcome to borrow one of mine anytime to try it out. I have two.
They quit doing this in hydraulic and pumping systems untold decades ago when both power consumption and maintenance frequency and costs started being an issue. Its all centered around Conservation and reliability centered maintenance. It is not at all efficient and wears the pumps out many times faster due to the additional work placed on them. Why do the work (power and heat) to pump all that water only to waste it back to the sump when you can simply add head via an inline valve and reduce the work being performed, lowering the 24/7/365 power consumption and $$ spent as well as reduce the heat generated and the noise the additional work causes and make your pump last longer in the process since is not working as hard. Explain your reasoning or justification please? Read the two rules of science I mentioned when you have time and it will make sense. It is a bad idea and not one I would ever recommend, especially in an open forum its so bad.

 

[KoleTang]

Well I had better fix my return then. Thanks for the tip AZ.

 

[Reef head]

Not to go against you, but I get nothing of that. If you have a tee on a centrifugal pump you are going to increase power consumption? If you run a direct line with a ton of head pressure on centrifugal or cavitation is occurring would increase power consumption on a DIRECT drive application. Worse case scenario, install a micro vfd that plugs into your panel and away you go. Costs less than 80 bucks.

 

[AZDesertRat]

You probably have more than 3' of headloss when you calculate friction losses in the piping and fittings and the vertical distance between the sump water level and the display water level or wherever the return dumps back in but the pump is still way oversized for your overflow box. It is not bad to throttle or restrict the flow of an oversized pump up to a point, say 25-30% but if it is really approaching 50% oversized you may have issues since there are built in electrical inefficiencies such as the weight or the rotor or magnet, shaft and impeller, friction losses due to the larger rotating element and associated heat gains etc. I would eventually look at either a smaller pump or a larger overflow box long term. It depends on your display and sump size and capacity and your corals or inhabitants as to which way you go, more flow if you have a larger display and sump which can handle it or SPS and LPS hard corals which like higher flows or a smaller pump if you have soft corals and/or a smaller display or sump or even smaller protein skimmer that may perform better at lower flows/velocities through the sump. There is no one right or wrong size or answer in this hobby but some are better than others,especially over the long haul. As probably most everyone would agree, research before you buy so you only have to do it once. Sites like this are a good resource and Reefing Madness usually has some good advice! Being a Moderator and contributor to many forums and part of the Team on others I know it can be a thankless job.

 

[AZDesertRat]

Reef Head, centrifugal pumps are a different animal and hard to understand, the two laws of hydraulics go into great detail on why that is and can explain it much better than I. Again a Kill A Watt meter proves it as does a digital thermometer, flow meter, pressure or head gauges and valves to add the restrictions.
Many years ago when part of Team RC I did a big write up on pumps I tested under controlled conditions side by side and documented head, flow, heat, sound and most of all the drop in power consumption when you add head via a valve in the discharge. We use it in engineering and hydraulics every day.

 

[Reef head]

I'm going to agree to disagree.
1 if you bleed pressure off it will not increase head pressure. Installing a valve and closing the valve on a closed loop system will increase head pressure and would increase power consumption on a direct link aka Lovejoy. The tee back to the sump will not increase head pressure. Do I think it is a waste to run a tee back.... yes.
2. The magnet is installed in these units to only allow so much torque. These units can produce 75psid which would blow the pvc pipe apart along with the housing. The dc motor will only spin so fast and the rest is slip. If there is not as much water movement through the pump with it being throttled back, yes that is where your heat will be. Volume vs. Time.
3. How much more amps are you drawing with installing a tee? None. How about valving down? More, if a direct drive. Rif is the only way to increase heat

 

[AZDesertRat]

You are correct, bleeding water off does not add head, which is why it consumes more power. A centrifugal pump is like a fan, not like a positive displacement pump. When you do add head, you decrease the flow which reduces the work required of the pump. When you bleed the flow or pressure off, the pump has already dne the work to pump that water, only to dump it back in the sump so the damage, or power has already been consumed. Again, its not my law or theory, this was proven in the late 1600's by Isaac Newton, later in the 1700's by Bernoulli and again in later years with the Affiniy Laws which apply to centrifugal force, speed and impeller diameters and how the affect each other. It is not easy to understand and if you agree or not it is fact, not my opinion. Maybe a hydraulic engineer could step in and explain it better without having to read all the theories. Really the easiest way though is with a Kill A Watt meter to record power consumption with the two modes we are talking about, bleed off flow or restricting flow.

Again we are talking about centrifugal pumps which are similar to a fan in that there is centrifugal force in play and a calculated amount of slippage or wastd energy unlike a positive displacement constant speed pump.