2 main pumps or 1 big one?

gotpancit

gotpancit

Member
I'm at the point where I'm going to look for pumps and was wondering if I should get two pumps for redundancy if one breaks I'll at least have one pumping. I'm aiming for 1400gph which is a pair of MD 40 710gph pumps at $80/ea *** Do not post links to competitors sites -Sep or one blueline 70 at 1500gph at about $200 ***It would seem cheaper to go with the pair of MD40's but I don't know the quality of them.
What are your thoughts?
***oops sorry mod...actually I was looking on swf and didnt find any pumps!
 
keith burn

keith burn

Active Member
how will you use the pumps?
not good to have 2 return pumps.
but if one is for the return and one is for a skimmer ok.
 
salt life

salt life

Active Member
it is easier to use one big pump so it will split the gph, if you do 2 small pumps i think the only problem would be matching the flow rates but if they are the same gph i don't see why not, but JMO.
 
wangotango

wangotango

Active Member
Assuming you determined what gph you needed to return, and divided that by two it might work. But if one of the pumps fails the other won't be able to return the extra water back. You could always run both throttled back so that they match, but it would be expensive running two pumps and only be using 50% of each capacity.
IMO I'd just run one as your main return pump and have an extra just in case. Make sure you either have clamps or union-valves so you can take the pump out if you need to.
Don't forget about head-loss too. Just because the pump pumps 700gph doesn't mean you're getting 700gph once it pumps from the sump back up to your tank.
-Justin
 
gotpancit

gotpancit

Member
Ok to clear things up I have a 140g tank that needs approx 1400gph total. If I have two return pumps that pump 710gph each thats 1420gph. OR I can have one pump that pumps approx 1500gph.
The reason I'm considering two pumps is in case one fails, I will at least have one pump that will be working, but at half the required flow rate. My thought was, half the flow rate is better than no flow rate.
So I'm just wondering if the risk of having two pumps (and more possibilities of leakage) is worth the safety I can have if one pump goes out.
But I guess wango is right...just buy a spare. Thats an expensive paper weight, but I guess it could get more expensive if I lose my whole tank.
 
saltfan

saltfan

Active Member
Originally Posted by gotpancit
http:///forum/post/2950573
Ok to clear things up I have a 140g tank that needs approx 1400gph total. If I have two return pumps that pump 710gph each thats 1420gph. OR I can have one pump that pumps approx 1500gph.
The reason I'm considering two pumps is in case one fails, I will at least have one pump that will be working, but at half the required flow rate. My thought was, half the flow rate is better than no flow rate.
So I'm just wondering if the risk of having two pumps (and more possibilities of leakage) is worth the safety I can have if one pump goes out.
But I guess wango is right...just buy a spare. Thats an expensive paper weight, but I guess it could get more expensive if I lose my whole tank.
Expensive?? Hmm. One Hydor Koralia #4 (1200gph) is only $50. A #3 is only $40 at 780gph. Just get 2 of those...
 
turningtim

turningtim

Active Member
I would check the wattage draw for both 1 vs. 2. I think you'll be better off with a bigger external. As wango said are you including headloss in your calcs. I haven't seen anything about drain size? You don't have to get all your flow from your return....
 
snakeblitz33

snakeblitz33

Well-Known Member
Originally Posted by keith burn
http:///forum/post/2950342
not good to have 2 return pumps.
Why? I have used two return pumps on the same tank before? I have also used more then one return pump on an entire system of 30 tanks before, I don't see why it's a bad thing?
Originally Posted by Salt Life
http:///forum/post/2950359
it is easier to use one big pump so it will split the gph, if you do 2 small pumps i think the only problem would be matching the flow rates but if they are the same gph i don't see why not, but JMO.
Again, I don't see why they have to be the same gph? If the tank is level, then the water being returned into the tank would increase the water level at the same rate regardless of how much one pump is flowing vs. the other.
Originally Posted by gotpancit
http:///forum/post/2950573
Ok to clear things up I have a 140g tank that needs approx 1400gph total. If I have two return pumps that pump 710gph each thats 1420gph. OR I can have one pump that pumps approx 1500gph.
The reason I'm considering two pumps is in case one fails, I will at least have one pump that will be working, but at half the required flow rate. My thought was, half the flow rate is better than no flow rate.
So I'm just wondering if the risk of having two pumps (and more possibilities of leakage) is worth the safety I can have if one pump goes out.
But I guess wango is right...just buy a spare. Thats an expensive paper weight, but I guess it could get more expensive if I lose my whole tank.
Are you dead set on external pumps? You can get two Mag Drive 7's ... which are internal pumps. If you don't have the room in your sump for two mag 7's, you could get something from little giant.
Your right, if one pump goes out, and you don't have a replacement, some flow through your sump is better then no flow at all. Buying one large return pump and it's replacement is going to cost a pretty penny too.
I guess it comes down to if you want to take the risk. But as far as I am concerned, you can run two pumps as easily as one.
Originally Posted by TurningTim
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I would check the wattage draw for both 1 vs. 2. I think you'll be better off with a bigger external. As wango said are you including headloss in your calcs. I haven't seen anything about drain size? You don't have to get all your flow from your return....
Tim makes a really good point. If running two pumps draws more electricity over time then just one pump, you may be paying out too much each month, and it would be easier to just get that one pump because of electrical cost.
While you don't need to get all of your flow from your return, you also don't want your sumps organisms to die from lack of flow and gas exchange. I suggest to also suppliment your internal flow rate with powerheads. (either Koralias or maxijets)
Good luck and have fun!
 
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