Little giant pump 3-MD-HC

[evandy]

Keep the inlet full size at 3/4", any inlet resstriction or fitting reduction size has a big reduction in the pumps performance. Reducing the outlet isn't a problem as with a valve on the outlet to throttle the flow down.

Isn't there a limit to this? If the tubing to feed the pump is 1/2", then puting a 3/4 to 1/2 reducer won't change anything.

 

[MrH]

PNW, like in Washington state?

Yes, on the peninsula...

 

[BrewBeemer]

Isn't there a limit to this? If the tubing to feed the pump is 1/2", then puting a 3/4 to 1/2 reducer won't change anything.

I would never use it that way, I would use a 3/4" inlet pump with 3/4" feeding it.
As far as using 3/4" tubing then reducing it down to 1/2" at the pumps 1/2" inlet this will have less tubing flow resistance vs using straight 1/2" but not that much of a difference. The biggest problem's at the pump with the 1/2" inlet vs 3/4".
When I dumped my March 809 pump for a LG that has 3/4" inlet I used a reducer to step the 1/2" PVC to 3/4" on the LG vs the March pumps 1/2" inlet just to get the Koi ponds waterfall flowing again for their O2. Ok it flowed until I repiped with all 3/4" on the inlet side a couple days later. With 3/4" at 7' long for the inlet vs the 1/2" before the LG pump woke up big time. They hate any inlet flow resistance vs the size that came with the pump.

 

[GreenMonti]

I can't think of any pump that like's a smaller intake then what it comes with. The venturie is designed around the flow input. I also think pump placement has a lot to do with the different experiences with said pumps. Some have little, and some have heavy head pressure by comparison. That's right, head pressure goes both ways. A 1/2" drain at 1 foot has much less drainage then a 1/2" drain at 4 feet. This also applies to a single tier vs a double tier stand.

 

[BrewBeemer]

I can't think of any pump that like's a smaller intake then what it comes with. The venturie is designed around the flow input. I also think pump placement has a lot to do with the different experiences with said pumps. Some have little, and some have heavy head pressure by comparison. That's right, head pressure goes both ways. A 1/2" drain at 1 foot has much less drainage then a 1/2" drain at 4 feet. This also applies to a single tier vs a double tier stand.

That about says it all about a manufactures pump with all the engineering designed into it then a pump owner trying to use it for what it was not designed or used as with a do it yourself improved design or use added.
Frictional tubing fluid flow losses alone without any head pressure not counting the diameter, length, number of bends plus the fluids viscosity all add to the pumps performance output or lack of. Thru digging wells in the 70's plus being around a family friend that was in the pump bunsiness for over 60 years I was always told to use the manufactures pumps high output specs and cut them in half to meet real life or world performace flows after it's installed. Pressures at different flow volumes will change also. If this matches your demand of a selected pump you've picked the right pump. This with centrifugal pumps. Ranch high pressure piston pumps pushing uphill 350' to a tank is a totally different topic on specs as well muti stage submersible well pumps. This has worked for me keeping me out of trouble with selecting the proper pumps the past 41 years. With the offer of two brand new March 908 pumps for $75 I jumped on them and only later found out I wasn't happy with their outputs. Good thing I unloaded them right away and went to LG pumps 4 years ago and never looked back. My $0.02 on this topic.

 

[benbradford]

I previously owned an aquarium business, and had fairly good luck with the little giant pumps, however, I did see some old models fail at times. My favorite pump when installing and personally, was the mag 7 or mag 9 or mag 12 pumps. I have not been able yet to find any info on the temperature rating of these, but for the price and the performance, they were always my favorite. I found a phone number and am thinking of calling during business hours to see if they can give some info on the temps...

 

[FenoMeno]

I am a bit confused on the 3/4 inlet to 1/2 out.
I just bought @ of these for my build, and looking for correct disconnects. I bought all 1/2" silicone as all my other ball valves were 1/2.
I understand the restriction of a reducer, but how do you get around it if everything else is 1/2"? (this is my first build)

Now I am not sure what size connects to buy either...

 

[TomRep]

I e-mailed Supreme (Mag pump company) and they do not make any Mag pumps to the standards we need.
tom

 

[diatonic]

I am a bit confused on the 3/4 inlet to 1/2 out.
I just bought @ of these for my build, and looking for correct disconnects. I bought all 1/2" silicone as all my other ball valves were 1/2.
I understand the restriction of a reducer, but how do you get around it if everything else is 1/2"? (this is my first build)

Now I am not sure what size connects to buy either...

On the inlet I used a 3/4" NPT close nipple, 3/4" NPT 90 elbow, 3/4" to 1/2" reducer bushing, to a 1/2" NPT male QD. Outlet has a 1/2" NPT ball valve to a 1/2" NPT male QD. Works great. I also use 1/2" silicone.

 

[FenoMeno]

Diatonic,
Just watched your video: March vs. LG --Thanks for the demo!
I am anxious to try my 2 new pumps.
I guess watching your whirlpool with the 3/4 to 1/2, doesn't worry me anymore. It looks like it did fine. Perhaps 3/4" all the way would really make this pump sing, but for our purposes...well your video shows it all. Thanks again.

btw, how do you have that mounted?

 

[FenoMeno]

Actually, my thoughts for the inlet were to order 3/4" barb, and try to squeeze my 1/2 silicone over it, and skip the reducer. Anyone try that stretch?