GPH Rates

Ok so I don't fully understand flow rates yet and this may sound dumb but I
don't want to be wrong and throw money away but if a overflow is rated
at lets say 300gph should the return pump be rated the same or higher ?
and I am also bidding on a skimmer on ebay and the seller said it has a
pump for it that is rated at 1200gph does the pump for the skimmer have
anything to do with the rate of the return or overflow ? I don't want to
keep bidding and have something to powerful for my 75g tank.

 

No, you don't want your return pump to be pumping more water than your overflow can handle, otherwise you will end up overflowing your tank because your return can't keep up. With that said, you have to take several factors into account (like head height) that affect how much a return pump actually pumps. For example, a 700GPH pump might only return 250GPH if it has to lift the water to a head height of 5 feet.

The skimmer pump should not have any impact on the equation. That just means how much water is going into/out of the skimmer and doesn't affect your return at all.

-JB

 

The website that i am looking at has a chart like this does this mean if my return height is going to be 5.7ft will it be returning 294gph?



Model Flow Rate Max Head
400 106 gph 2.1 ft
900 247 gph 4.1 ft
1100 294 gph 5.7 ft
1800 475 gph 7 ft

 

Double post. Sorry.

 

If you buy the model 1100 that will be your flow rate at that listed head pressure. And that head pressure is the max that pump will do, so if you have to go higher than 5.7 then you want the next model pump, the 1800.

 

Ok now that I understand that what would be a good GPH rate for a 75g tank ?

 

The recommended rate is 10x the tank volume per hour.

 

i prefer 4x tank volume per hour.

 

i use a mag9.5 in my 90 if that helps to give you any type of relation

 

i use a mag9.5 in my 90 if that helps to give you any type of relation

 

The flow between my tank and sump is considerably less than 10X the display tank volume. My "internal" flow in my display tank is considerably higher than 10X (more like 100X). IMO, too much flow between your tank and sump is counter productive. You want to give the skimmer time to do it's magic.

 

+1 
Exchanging the water between display and sump takes your filtered, heated/cooled, treated water from all of the gear you have running in your sump (i.e reactors, skimmers, filters, heaters, chiller, etc.)  and exchanges it with the dirty water from your display.
I agree with the 4x-6x turnover rate.  I think I'm running between 4x and 5x (120 gallon tank - about 500 to 600 GPH).  Remember, when they say your corals like high flow (20x to 50x, etc.), they are referring to the overall flow rate which is a total between what your power heads are putting out and your flow between sump & display.
--AJ

 

I use lots of flow through my sump. A. Because my sump is setup with a section that receives all the return flow, and has a skimmer/pump that pulls the level down at the same rate and all the water going through the sump gets skimmed, then dumped on over to the next section. B. I do not use powerheads in my display, I just use a closed loop and try to keep everything suspended. I clean the sump section out of anything that settled, every other week. Also I do not always use my skimmer, just when I see fit, either to prolong water changes, or if I felt a need to overfeed.

 

to go along with the flow rate question here, how much water flow do you want going through your chetto / refugeium area then that same amount, more, or less 2x, 5x, or 10x ?