[MikeV]

I am in the process of upgrading my return pump from my sump. I have a 55g reef/fish tank. I am replacing a 750gph return pump with a 1200 gph pump and adding a second overflow box. Is this overkill because it looks somewhat harsh inside the tank, although the corals aren't getting thrashed and the fish don't appear to mind. Besides, I now have a great micro-bubble battle on my hands

[RyanG]

Generally you want at least 10x the size of your tank, so in your case that would be about 550GPH. I would say 1200GPH is overkill unless you have a lot of head loss.

If your fish and corals don't seem to mind for the time being you would leave it how it is. However you are using more electricity and driving up your electricity bill.

[WILLIAM1]

I use a mag 12 on my 90 and I had to put a gate valve on to slow down the return a little...

[realfishy1]

I am running a hammerhead pump on my 230 gal reef this puts out 5800 gal/h . I say the more flow the better .

[Taras1]

I have a Mag 12 on my 90 gal and several return ports. It adds a bit of turbulence.

[nunch]

Originally Posted by WILLIAM1

I use a mag 12 on my 90 and I had to put a gate valve on to slow down the return a little...

How long have you had the gate valve installed? I've been told there a pain when used in salt water cause they fowl up and u need to replace them every few weeks. unless your not adjusting too often then, i'd imagine, they'd last a bit longer.

[nunch]

Originally Posted by realfishy1

I am running a hammerhead pump on my 230 gal reef this puts out 5800 gal/h . I say the more flow the better .

not necessarily, depends on what you have in tank. too much flow can cause micro-bubbles and your sand to be blown around.

Water movement

Water movement is important in the reef aquarium with different types of coral requiring different flow rates. At present, many hobbyists advocate a water turnover rate of 10x: 10 volums per hour x aquarium capacity in gallons = required flow in gallons per hour. This is a general rule with many exceptions. For instance, Mushroom Coral requires little flow and is commonly found in crevices near the base of the reef. Species such as Acropora and Montipora thrive under much more turbulent conditions in the range of 30 to 40 times more flow, which imitates breaking waves in shallow water near the tip of the reef. The directions which water pumps are pointed within an aquarium will have a large effect on flow speeds.

I added the highlighting.