Mag 7 or Mag 12 w/gate valve

[stevearthur]

I am stuck in my decision of which pump to buy. I have a $60 gift card from Petsmart and I'd like to use this money for my pump. Petsmart only sells through mag 7 then jumps to mag 12. My dilemma is to get the mag 7 or the 12 and use a gate valve to restrict the flow. Here is the system that I am planning.

 

[Robin Goodfellow]

hi.
Well, Mag 12 use 40Watt more electricity than the Mag 7, so you will be like having a 40W heater that is always on in your sump 24/7...Just something you need to consider if you are paying for your electric bill and have problem with heat during summer.

 

[stevearthur]

I live in central California where the temp ranges up to max of 110 or so during the summer. My main concern was the amount of current I will need for my tank. I am planning a few fish and soft corals, perhaps hards when I can afford a MH.

 

[Robin Goodfellow]

hi.
Save some money and get the Mag 7, since once you put a MH on your tank, you will be screaming for chiller immediately if you don't need it before the pump purchase... unless you don't feel that the Mag 7 will give you enough flow.

 

[mountainbiker619]

here is the situation you may run into...you get the Mag-7, only to find out that it will not return as fast as the aquarium puts into the sump. I have found it is always best to buy bigger and install a gate valve to control the output. I have a Mag-24 on my 60..yes, I have it cut back alot, but I knew before I even started the plumbing on my aquarium that the Mag-24 along with gate vavle would suite my needs.

 

[Robin Goodfellow]

hi.
There may be a complication with SCWD (back pressure, etc), but for a run-of-the-mill tank/sump setup, there is no concern about a pump not returning as fast as the aquarium is draining into the sump. This is because the aquarium (if properly setup) will only drain as much as the return pump is pushing up. If you are not convinced, try to think about the situation when the power to the return pump is cut off (during power failure, broken pump, temporary shut off, etc.). In this case, you are going from a Mag-12 (or Mag-24 in your case) to a Mag-0 ( :wink: ), and you are saying that a Mag-7 will have problem already?

 

[jhaag]

Robin's right. As long as you have an overflow, or at least a stand pipe, it shouldn't be possible for the tank to drain anything more then the return pump provides to it. Whether that's 1gph or 1000gph. That's becuase any extra water added to the tank by the return pump increases the water level in the tank which floods over the overflow and then back down the drain. If it were any different, you would never be able to keep the aquarium at a constant level. A little algea buildup on the return and you'd have a wet carpet. Just imagine what would happen if you ever had a power loss... Surf's up....