I have a 90g tank, and I picked up a 40g breeder tank the other day from Petco while it was onsale. I am building a diy wet/dry filter. I am just about to start on the plumbing part, and I have a good idea how to do most of it. The question I have is what is the best way when plumbing the return off the pump, so that I can adjust the amount of return water flow to the tank, but not ruin the pump. I have seen where some people come right off the pump then put a T in there, so that the valve controlling the water back to the tank is closed a lot, the remaining amount of water will just dump right back into the sump.
Working on sump project, need input on plumbing return side.
- Thread starter poormonkey
- Start date
A "T" with a ball valve to bleed excess flow into the sump is an option, but the best idea is buying an appropriately sized pump so that you don't have to worry about bleeding off excess flow; if you are doing this you are running an oversized pump and that's just a waste of electricity and $.
What pump do you plan on using?
What pump do you plan on using?
You have my exact setup. A 90 gallon tank with a 40B sump. I use a mag drive 12 for return which is T'd off and a portion returns to a refugium in my sump. The flow to the tank is also regulated by a ball valve.
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I recently bought one of those Kill-o-watt devices and put it on my aquarium. At the beginning of the month my aquarium consumes 430 watts of electricity. At the end of the month it consumes 380 watts of electricity. The reason for this difference is that I run a large Hayward EC40 DE filter and over the month the DE powder plugs and the flow through the filter slows. The EC40 has a nice feature, a handle on the top to knock all the DE powder off the screens allowing it to recoat the screens with a fresh layer of exposed DE powder... allowing more flow through the filter. At the end of the month when I recharge the filter by knocking the DE powder off the screens the flow returns and the electrical consumption returns to 430 watts.
The hydro dynamics of a non-positive displacement pump are such that the more water the pump pushes through the pump the more work it is doing and the more electricity it consumes. The hydro dynamics of non positive displacement pumps means that a restrictor valve will actually lessen the load on the pump. Many people have a hard time accepting this counter intuitive fact.
Direct drive non-positive displacement pumps are often designed to dissipate the heat the motor produces through the shaft of the impeller into the liquid being pumped. When these direct drive non positive displacement pumps are restricted too much... heat will build up in the motor and seals of these pumps which will likely shorten the service life of these pumps.
Most aquarium pumps are magnetic drive, i.e. the impeller is not directly coupled to the motor for the express purpose of mitigating the heat dissipation into the water (It also eliminates the need for the impeller shaft seal which is a major source of leaks in direct drive pumps). Since the impeller is not used for pump cooling in magnetic drive aquarium pumps the flow of these pumps can be reduced to near zero with no negative effects to the pump. If anything the lower energy usage of these pumps when flow restricted will likely extend the life of the pump ever so slightly.
I am SURE I will be attacked for this blasphemy... but if you consult a hydraulic engineer versed in the design and operation of non-positive displacement pumps I am confident their educated opinion will confirm what I have said here.
I will take cover now and wait for the attacks to begin.
The hydro dynamics of a non-positive displacement pump are such that the more water the pump pushes through the pump the more work it is doing and the more electricity it consumes. The hydro dynamics of non positive displacement pumps means that a restrictor valve will actually lessen the load on the pump. Many people have a hard time accepting this counter intuitive fact.
Direct drive non-positive displacement pumps are often designed to dissipate the heat the motor produces through the shaft of the impeller into the liquid being pumped. When these direct drive non positive displacement pumps are restricted too much... heat will build up in the motor and seals of these pumps which will likely shorten the service life of these pumps.
Most aquarium pumps are magnetic drive, i.e. the impeller is not directly coupled to the motor for the express purpose of mitigating the heat dissipation into the water (It also eliminates the need for the impeller shaft seal which is a major source of leaks in direct drive pumps). Since the impeller is not used for pump cooling in magnetic drive aquarium pumps the flow of these pumps can be reduced to near zero with no negative effects to the pump. If anything the lower energy usage of these pumps when flow restricted will likely extend the life of the pump ever so slightly.
I am SURE I will be attacked for this blasphemy... but if you consult a hydraulic engineer versed in the design and operation of non-positive displacement pumps I am confident their educated opinion will confirm what I have said here.
I will take cover now and wait for the attacks to begin.
That actually makes sense. If the magnetic impeller moves slower due to water restriction, it is using less power (work over time). If its using less power, less current is being induced from the driving magnet, and it is working less too. My only question is how do these pumps cool down. I was under the impression water flow still cools them, as I have a rio submersible pump with a loose impeller that I use for water changes. When the impeller jams, the motor still vibrates some and the housing heats up more than it normally would while functioning properly.
The impeller does not actually slow down when less water is flowing through the pump. It just takes less energy to move the impeller because the impeller is moving less water. The motor simply sees less resistance and hence has to do less work. If you completely cut off the flow through a non-positive displacement pump the water simply spins in the impeller compartment with the impeller which takes less energy than actually moving new water through the pump. Eventually heat will build up slowly in the impeller compartment due to the lack of new water.
When the impeller gets stuck in the impeller casing in a magnetic drive pump the motor should still spin but with a lot of resistance due to the impeller not moving. This is why the pump motor will heat up when the impeller is stuck.
The motors in aquarium pumps are quite efficient. An inefficient motor will consume electricity just to keep operating even if it is doing no work. This energy is transformed into heat. Aquarium pumps do not produce much heat because they are quite efficient. The majority of the heat an aquarium pump produces is shed through the pump casing. If the pump is submersed the heat will be carried away by the water. If the pump is not submersed the heat transfers into the surrounding air.
When the impeller gets stuck in the impeller casing in a magnetic drive pump the motor should still spin but with a lot of resistance due to the impeller not moving. This is why the pump motor will heat up when the impeller is stuck.
The motors in aquarium pumps are quite efficient. An inefficient motor will consume electricity just to keep operating even if it is doing no work. This energy is transformed into heat. Aquarium pumps do not produce much heat because they are quite efficient. The majority of the heat an aquarium pump produces is shed through the pump casing. If the pump is submersed the heat will be carried away by the water. If the pump is not submersed the heat transfers into the surrounding air.
Oughtsix, the only people who would attack you are people who don't know what they are talking about...you are on point.
I've hooked my pumps up to a kill-a-watt device and would watch the wattage drop as I valved the pump back, so I know what you are referring to.
But if your comment was directed at what I wrote about an oversized pump being a waste of electricity and $, I will stand by that statement. To give you a real world example, let's take a setup with a desired flow of ~3,000GPH and compare an oversized pump with an appropriately sized pump.
Reeflo Hammerhead Gold @ 20' of head pressure does 3,000GPH and consumes 325 watts
Reeflo Super Dart Gold @ 6' of head pressure does 3,010GPH and consumes 175 watts
Sure, you can valve the Hammerhead pump back to the equivalent of 20' of head pressure so that it's only pushing 3,000GPH on 325 watts; valved back it will use less electricity than if it was running wide open with no head pressure (in which case it uses 350 watts), but why would anyone do that if you can get a Super Dart Gold that will give you the flow you want (3,010GPH) on almost 50% less electricity (175 watts)?
Hope that clarifies the point I was trying to make by recommending OP purchase an appropriately sized pump for his setup as opposed to looking to valve back or bleed off excess flow. Although if he has to, I fully agree that there's no problem in doing so and it will actually result in the pump drawing less power.
I've hooked my pumps up to a kill-a-watt device and would watch the wattage drop as I valved the pump back, so I know what you are referring to.
But if your comment was directed at what I wrote about an oversized pump being a waste of electricity and $, I will stand by that statement. To give you a real world example, let's take a setup with a desired flow of ~3,000GPH and compare an oversized pump with an appropriately sized pump.
Reeflo Hammerhead Gold @ 20' of head pressure does 3,000GPH and consumes 325 watts
Reeflo Super Dart Gold @ 6' of head pressure does 3,010GPH and consumes 175 watts
Sure, you can valve the Hammerhead pump back to the equivalent of 20' of head pressure so that it's only pushing 3,000GPH on 325 watts; valved back it will use less electricity than if it was running wide open with no head pressure (in which case it uses 350 watts), but why would anyone do that if you can get a Super Dart Gold that will give you the flow you want (3,010GPH) on almost 50% less electricity (175 watts)?
Hope that clarifies the point I was trying to make by recommending OP purchase an appropriately sized pump for his setup as opposed to looking to valve back or bleed off excess flow. Although if he has to, I fully agree that there's no problem in doing so and it will actually result in the pump drawing less power.
With taking into count the pump head loss, I was thinking a mag 7 or mag 9 pump. However, I see pdandy with the same setup went with a mag 12 pump. So, now I have to rethink what size pump to get.
Nope, I wasn't referring to your comment about right sizing a pump. I think that selecting the proper components of proper size and capacity is just good engineering. I was referring to other threads on here in which other members insisted that throttling aquarium pumps would ruin them. I gave up arguing with them. Not a reference to your post. A pump that is way too big would just be a waste of electricity. My only point was that throttling a pump a bit to tune for the flow you want is a safe practice.
P.S. I run a Quiet One 3000. It has never failed but I will purchase a different brand next time. Sometimes I have to restart it several times to clear the impeller casing of air.
