mag drive external plumbing and flow question?

jazzlvr123

Guru Class Expert
Jul 3, 2007
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Hi I was wondering on peoples thoughts about plumbing the mag drive pumps externally. I purchased a brand new mag drive 9.5 pump (runs 950 gph) to plumb in to my closed loop system on my 60 gallon cube.

However when the day came to plumb the tank a friend of mine said the mag drive pumps leak if plumbed externally. so I went ahead and plumbed an eight year old used little giant pump which claims to have just as much flow as the mag drive however by the time it makes it though the ocean clear filter (which current has a reading of 3 psi with the valve completely open) and mazzei injector (on separate loop) the flow coming into the tank is less than impressive (my guess is because of the pumps age).

so I was thinking about replacing the little giant pump with the seemingly more powerful mag drive pump. my question is do you think its safe to plumb the mag drive externally without worrying about a leak or should i leave my setup be and just deal with the sub par flow rate making it into my tank. also is 3 psi flowing though the ocean clear too little of flow? seems like it to me.

heres my current flow Rate with the little giant pump:
IMG_0948.jpg


heres the little giant pump i plan on replacing:
IMG_0949.jpg

IMG_0935.jpg


and heres the pump I plan on putting in as a replacement (mag drive 9.5):
IMG_0954.jpg



do you think that I am safe to replace the pump?
 

jeremy v

Guru Class Expert
Apr 17, 2008
166
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Jazzlvr123,

I don't know exactly what your Little Giant pump is pumping right now since I couldn't quite read the exact model from the picture you provided. It was just a little bit too blurry. I can tell that by looking at your system you have the canister and mazzei plumbed in parallel, so 3psi is going to be about exactly the head your pump sees with all the other losses and benefits factoring in as well (and mostly canceling each other out). 3psi x 2.3 = 7' of head. Your new Mag Drive 9.5 will flow around 600-650gph at that head level, so if you are happy with that flow rate you should be fine.

If you want to know what you are flowing right now, try to find the pump flow curve online (for the Little Giant pump you are running now) and see what the flow rate is at 7' of head. That should give you a rough estimate of how much your flow would change from switching pumps.

I have never used a Mag Drive pump externally to comment from experience on the leakage aspect of your question. Just from looking at the pump from a design perspective, I would say that the pump itself looks well built and there are actually very few places that could even leak compared to many other pumps. I would bet that most leakage issues that people may be having with that pump are probably due to the pump leaking from the threaded connections (from not using Teflon tape on the threads when screwing together your plumbing runs off of the pump's threaded inputs and outputs) rather than the actual pump housing leaking. I could be wrong though, so maybe someone else has more for you in regards to the question of leakage.

If you are nervous about the pump leaking, possibly go ahead and install it and just put the pump inside some sort of a container (as large and deep of a container as you can fit in your tank stand) so that if it does leak the container will catch the water for a while before the floor starts to get wet. That would allow you to possibly notice the water level dropping in the display tank so you could turn the pump off and fix the problem before the water actually started to go out onto the floor and/or do any damage.

Have a good one, Jeremy
 

JDowns

Lifetime Charter Member
Lifetime Member
Jul 27, 2007
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New Hope, Pennsylvania
I've had 2 9.5's running externally for over a year, and a Mag 7 for just about six months, and have never had a leak.

I've read that people have had them leak though, but that has mostly been from the saltwater side of the hobby.

Word of caution. Do not use to much tape to cause the housing to break on the female side.
 

jazzlvr123

Guru Class Expert
Jul 3, 2007
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turns out the little giant pump I'm using is only 510 GPH and after 7' of head its about 400 gph. even the mag drive is at about 800 gph after 7' of head. so I'm thinking of buying a new pump altogether now. I looking at a Pan World 100 PX-X Aquarium Pump which will give me 950 GPH after 7' head which is more of what I was looking for in the first place.
 

veryl

Junior Poster
Oct 4, 2007
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80
St Louis Park Mn
I bought a Mag 12 suppose to pump 1200 gph but had 3/4" fittings and instructions that said in order to pumps the 1200 gph i'd have to step it up to 1 1/2'' pipe. Bought a different pump mag 12 still in the box. Maybe step it up to 1" pipe and use on a 90 gal tank.
 

Tom Barr

Founder
Staff member
Administrator
Jan 23, 2005
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Come on Kyle, you know you wanna buy the RT40 iwaki:p

Cheaper than anyone, I'll even pay for shipping and toss some weeds in there for you.

950 at 4ft and so about that with the set up you have, which is what I run on my 180...............more than all the pressure and flow you might need.

Regards,
Tom Barr
 

jazzlvr123

Guru Class Expert
Jul 3, 2007
108
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16
Tom Barr;30267 said:
Come on Kyle, you know you wanna buy the RT40 iwaki:p

Cheaper than anyone, I'll even pay for shipping and toss some weeds in there for you.

950 at 4ft and so about that with the set up you have, which is what I run on my 180...............more than all the pressure and flow you might need.

Regards,
Tom Barr

okay tom you win. pm sent :D
 

jazzlvr123

Guru Class Expert
Jul 3, 2007
108
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one more question. how much head is added to the equation when you reduce a pump with 1" input and output to a system that in plumbed with 3/4" piping?
 

Tom Barr

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Jan 23, 2005
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The RT40 is 3/4" that's why the flow is less than the RTX40, which is 1".
So the loss in head reduction will be less, also, you have in let head pressure as well to account for as the system is sealed, unlike sump situations.

So it's not just all head pressure going up.

If you make the in let pipe 1" and keep it short/few turns etc, then at the last possible spot, next to pump, add a 1-> 3/4" reducer, this will help max the in let pressure coming in better.

Regards,
Tom Barr