Confused about gph

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Horsegirlmaddy

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Nov 13, 2012
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Hello guys! I bought a used 60 gallon tank for my future saltwater tank (FOWLR for now, possibly reef later on). It has a built-in intake and output system in the bottom of the tank that connects to a cannister filter in the cabinet, resulting in very few dead spots in the tank, and no unsightly hoses on the back of the tank. Now I just need a cannister filter for it! I've been browsing, but am very confused about how many gph I need. The big eheims I've seen to up to around 360 gph, for "up to 160 gallons". I thought flow had to be at least 10 times the capacity of the tank?? But I googled 6000gph filters, and it was only showing monster pond cannisters! Is there something I'm missing here??
 
The filter does not have to make up for all the flow. I like to keep my filter rate at between 4x-10x tank volume. The rest of the flow you can get from your skimmer (if its a HOB on the DT) and circulation pumps.
 
It might actually be better to plumb that to a sump, which will give you a lot more options as far as GPH on the return pump. A canister should be fine for a FOWLR, but they tend to be maintenance intensive in a reef since they trap so much detritus.
 
Rutrag said:
It might actually be better to plumb that to a sump, which will give you a lot more options as far as GPH on the return pump. A canister should be fine for a FOWLR, but they tend to be maintenance intensive in a reef since they trap so much detritus.

Hmmm. Any tips? Canisters I'm familiar with, sumps...not a clue.
 
Well first off 10x60=600 not 6,000 so if you got a pump in the 1,200 gph range that would do the turnover which you only need 5 or 6 times plus a skimmer and allow for the reduction in head height.
 
tonedogz said:
Well first off 10x60=600 not 6,000 so if you got a pump in the 1,200 gph range that would do the turnover which you only need 5 or 6 times plus a skimmer and allow for the reduction in head height.

Oh dear. I have no excuse for my terrible math. Big blush.
 
I've always heard 30-50% water volume. My 90 gallon tank would need between 2700-4500. I'm moving right at 3000 gph.
 
Hmmm. Any tips? Canisters I'm familiar with, sumps...not a clue.

At their simplest, a sump is just a container into which water flows from the tank and then is pumped back into the tank. In addition to the return pump, you can place other equipment such as the heater and a protein skimmer in the sump to get them out of the tank. It makes it easier to get to said equipment for maintenance and might make for a cleaner install.

What size are the holes in your tank? Do you have bulkheads in them? Are they behind a weir? (A weir is a wall with either slots towards the top or even teeth at the top.) In a typical drilled tank, the holes would be behind a weir. Water flows from the main part of the tank over or through the weir, and then moves through a standpipe into the sump. The return line is normally routed behind the weir, primarily to hide it.
 
The holes are quite large, and are fitted quite snugly with bulkheads. About the weirs, I don't know. I will take a couple pictures tonight to show exactly what the inside of it looks like.
 
Personally I wouldn't run a canister on a drilled tank. Most canisters are not designed to run under pressure and will leak if they are trying to hold back the volume of the entire tank. I know that some people have done this type of thing with success, but its not something that I personally would risk.
 
If it's the pre-drilled tank made by fluval it's meant to run with a canister, and they don't have weirs the just comes straight up into the tank
 
Woops pressed send instead of attach!

Also, the tank ran for ten years with a cannister, so I would say its probably fine, but I'd like to look into a sump as well.
I apologize for the terrible photos, the tank is in my garage at the moment with not much light or access to take close ups.
 

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