Why not 2 return pumps?

[Anonymous]

Ok is there a underlying reason why one cant have 2 external return pumps on their sump for circulation and not just one? I know folks have talked about closed loop systems for additional circulation. My question is why not just add the 2nd pump into your sump (I guess assuming you have one), instead of a closed loop? Just curious because I am setting up this huge tank and I have 2 return pumps to play with.

 

[Len]

No problem with running two return pumps. I do it. I prefer pump redundancy in almost every circumstance.

 

[Anonymous]

Ahh ok cool. Cause I'm going from a 90 gal to a 180 gal, I figured 2 externals would be good for circulation along with a few powerheads. Thanks for the info.

 

[ColdZero1]

The reason people use closed loop is because its possible that your overflows can't handle the extra water being pushed through them. If you're overflow is rated for 1000gph, then adding 2 AmpMaster 3ks is going to end in a mess. Instead people just use closed loop.

 

[Anonymous]

hi.
Also, in closed loop setup, the pump does not need to get the water all the way from the sump up to the tank. Less heat, less electricity, more flow than a second return pump.

 

[Anonymous]

Not only that, but a closed loop doesn't experience the head loss of a sump return pump, so you end up with more GPH out of the pump. It also is a much cleaner look than having multiple PH thoughout the tank. Just a Leonard said, nothing wrong at all with 2 return pumps, redundency is a good thing.

 

[Anonymous]

Isnt a closed loop just an overflow hole in the back of the tank which goes down directly to the external pump, then back up into the tank through outlets? This 180 has 2 of these bulkhead overflows, and I also have an overflow box I could use as additional overflow volume. I guess what I could do is use the 2 bulkhead overflows as closed loops and the overflow box as the main sump to tank transport.

 

[reefland]

I tried two return pumps (Iwaki MD70RLT and MAK4) on my 180 gallon tank and ther overflows just couldn't handle the volume. The overflow grates were the main issue in that water could not enter into the chamber fast enough and the center glass would go under water in seconds. In addition the water velocity in the sump from two pumps drawing water was so much that air bubbles couldn't reach the water surface quick enough before being sucked into the return pumps. I have a 4 foot long sump with 4 baffles already.

Even after removing many overflow teeth, I still couldn't get close and I moved the MAK4 to a closed loop. No problems now.

I plan on removing the MAK4 and redue all the plumbing to use an ampmaster 3k instead.

 

[ColdZero1]

I think the overflow holes in a closed loop system have to be underwater, or there is the chance that air will be sucked in and at the worst make the pump run dry enough that it breaks. At the least, you'd get a bunch of tiny air bubbles in the tank from it being chopped by the impeller. That can be fixed by just putting a 90degree fitting on the end of the hole inside the tank so it points down into the water.

 

[Anonymous]

Excellent point about the sump water velocity and bubbles. I'll have to try just the one return line and the other with a closed loop from the bulkhead. See this is why I come here .