Magdrive heat

thecichlidpleco · #1 01/09/2008, 09:19 PM

I got a free magdrive 9.5 from a friend, and used it on my sump that I created for my 40 gallon tank. The pump is in a 5 gallon tank that is gravity fed from a trashcan that recieves the overflow. I noticed today that my coral seemed to be mostly closed up, well 85 degrees does that I guess. I turned off my 150w heater, and will see how much that goes down, and then switch to opposite lighting for fuge instead of 24 hour if tank temp doesnt decrease. Would there be any other remedies besides buying smaller pump or getting chiller. I realize a 9.5 in 5 gallon is small but 55 stand is very narrow.

Pmolan · #2 01/09/2008, 09:27 PM

Mags run pretty hot. Here's an idea.

Build a platform of some sort in the sump. Install the mag on it so that it operates out of the water. Attatch a 90 degree elbow on the input so it reaches the bottom of the sump. Now mags are not self priming so what you have going for you is that when you shut off the pump the water will rise in the sump. When it has risin to the highest, the intake of the pump will be submerged so it will have water to restart itself. By keeping the pump out of the water, and they are also meant to be run inline as well as submerged, it will transfer less heat to your water.

m2434 · #3 01/09/2008, 09:34 PM

Mags are great pumps but I agree, they run really hot. Pmolan's idea sounds good to me. However, a fan or two pointed at the water would probably work just as good. The only issue is you will also increase evaporation.

thecichlidpleco · #4 01/09/2008, 09:44 PM

So only have the pump raised as high out of the water as the water is going to rise? With it in the water, when I turn it off, the 5 gallon fills up all the way, so I have litte room for mistakes. I have made too many mini floods already messing with this and my ro unit in the past month. also the discalimer says only run submerged.

AZDesertRat · #5 01/09/2008, 09:46 PM

The Mag will produce the same amount of heat submerged or outside the sump. The water inside flows around the motor windings in the potted material and picks up heat either way.

reefergeorge · #6 01/09/2008, 10:27 PM

My mag 9.5 heats 100 gallon total volume about 4 degrees.

Snowboarda42 · #7 01/09/2008, 10:49 PM

My Mag 9.5 doesn't heat mine at all.

I have it on a 40B with a 20G sump, and my tank temp will go as low as I let it.

I think that alot of the heat will be produced if you have the return line restricted, rather than diverted.

phurst · #8 01/09/2008, 11:03 PM

Careful running it externally:

I'm sure this was an anomaly, but none the less, it could have caused serious damage.

AZDesertRat · #9 01/09/2008, 11:21 PM

Returning flow back to the sump actually makes a centrifugal pump run hotter not cooler. When you restrict the discharge side you reduce the amount of work the pump is required to do and reduce the wattage consumed meaning less heat produced.
When you return part of the flow to the sump you are requiring the pump to work harder to pump the total volume of water even though you are only using part of the water. More work equals more power consumed whcih equals more heat produced.
All pumps create heat as they are not 100% efficient. Some are better than others though.

vanmo92 · #10 01/09/2008, 11:41 PM

My mag keeps my heater from running most of the time.

rickh · #11 01/10/2008, 12:41 AM

Quote:

Originally posted by phurst
Careful running it externally:

I'm sure this was an anomaly, but none the less, it could have caused serious damage.

What size Mag was that?? R

phurst · #12 01/10/2008, 08:00 AM

Seven.

thecichlidpleco · #13 01/10/2008, 09:36 AM

I do return it back to the sump and it is restricted to the main display another reason may be that I run 3/4" pvc all the way through and I think someone said it should be at least an inch. So say I created another diversion but to a different part of the tank, should that at least lower the temp since I should be able to open up the ball valve more?

thecichlidpleco · #14 01/10/2008, 04:19 PM

Maybe a smaller pump would end up being best?

Pmolan · #15 01/10/2008, 04:24 PM

Its winter now and its giving you problems. Just wait till the summer and it will be worse.

down and outman · #16 01/10/2008, 04:35 PM

I disconnect my heater in the summer. My Mag 7 and T-5's are all the heat I need.

thecichlidpleco · #17 01/10/2008, 05:06 PM

Pmolan, that is what I was worried about, 83 degrees, no heater, no fuge light.

reefergeorge · #18 01/10/2008, 05:31 PM

Quote:

Originally posted by AZDesertRat
Returning flow back to the sump actually makes a centrifugal pump run hotter not cooler. When you restrict the discharge side you reduce the amount of work the pump is required to do and reduce the wattage consumed meaning less heat produced.
When you return part of the flow to the sump you are requiring the pump to work harder to pump the total volume of water even though you are only using part of the water. More work equals more power consumed whcih equals more heat produced.
All pumps create heat as they are not 100% efficient. Some are better than others though.

From what I thought I knew about electricity. This would be wrong. So I put my kill a watt meter on my 9.5 and got 76 watts. I closed the ball valve a bit, and it went down to 69 watts. I don't know how this effects the heat output or lifespan, but it definitely lowers the wattage.

Snowboarda42 · #19 01/10/2008, 06:57 PM

Quote:

Originally posted by reefergeorge
From what I thought I knew about electricity. This would be wrong. So I put my kill a watt meter on my 9.5 and got 76 watts. I closed the ball valve a bit, and it went down to 69 watts. I don't know how this effects the heat output or lifespan, but it definitely lowers the wattage.

I think it works that way because the more closed you have it, the more the impellar is just spinning the water around, rather than actually moving it. Didn't think of it that way till now.