NEED MORE POWAH! Talk to me about pumps please.

[Oreo]

So I have an Eheim 1262. I'm getting 7gpm / 26.5Lpm from it. I'd like to have maybe not quite double that volume of flow. So I figure I've got two options:
A. Buy a second Eheim 1262 and run it in parallel.
B. Look for a larger pump capable of 14gpm / 50Lpm @ 2ft of head.

I'm figuring I've got 2ft of head pressure because of Eheim's craptastic graph. I'm not sure how accurate this graph is but I'm certain of my current flow capacity:

I've got 1" rigid PVC plumbing, if that makes any difference. I like the Eheim 1262 because it's been absolutely reliable for a few years now but I'm open to other models / brands if they have a good reputation.

I'm open to all manner of suggestions. Thanks in advance.

 

[Oreo]

Actually, I just saw this graph for the first time & now I'm stumped. I have no idea what my head pressure is. WTF?

ETA: OOOHHH... whoops... the graph above is in METERS, not feet. So I got about 2 meters of head pressure. Hmm... now I need to go back & double check which pump I've got. I either have a lot more head pressure then 2 meters according to below, or I have the smaller pump & in which case maybe I just need to upgrade. Hmmmm....

ETA2: You know what, I just took some measurements on this graph below and the (GPH) axis isn't scaled linearly so it's impossible to make any sense at all out of this graph.

I think the best I can figure is I've got 6 ft of head.

 

[dawnmarie]

Determining the "head" for your system should be pretty strait forward.
You need to know the vertical distance between the output of the pump and the surface of the water in the tank. This is slightly simplified, but, will give you a number that will serve your purpose.
If this number when applied to the chart yields a lower figure than what you are measuring then one of the following is likely happening.

The chart supplied by the manufacturer is in error
The filter is restricting the flow due to media choice or service interval
You might have some other significant restriction in the return

You might want to consider getting a 5 gallon bucket and measuring "actual" output on your setup.

 

[deeda]

I'm really confused what you are trying to do. IF you have a 1262 pump AND you are only getting 7GPM or 420GPH at 2 ft/head, something is wrong with the pump. The chart you referenced above shows you should be getting 13.2GPM or 792.52GPH at 4 ft/head.

What exactly is the setup you are trying to get the flow rate you want? I am assuming you are only using the pump and are returning the water to the aquarium from a sump. If the 1262 pump is mounted on the 2250/60/62 filter, then the flow rates quoted in the mfg. graph above will not be accurate.

 

[Oreo]

OK I double checked and I definitely have the Eheim 1262 and I am definitely getting 7gpm (yes, I measured.)

I'm not running a sump though. I'm running basically, a very large canister filter system with some other peripherals and the entire filter system is one floor below the aquarium. So there obviously is some restriction in my plumbing. BUT, none of that is going to change. I just need more pump to move more water through the system I've got.

 

[dawnmarie]

From the picture you have provided you could easily have 10 feet of head.
Measure from the outlet on the pump to the underside of the floor.
Add this to the dimension from the floor the tank is sitting on up to the surface of the water in the tank. This should get you pretty close to actual head height.
The effects of head combined with the restrictions from your canisters will slow a pump way down.

BTW, nice looking setup.

 

[Oreo]

From the picture you have provided you could easily have 10 feet of head.
Measure from the outlet on the pump to the underside of the floor.
Add this to the dimension from the floor the tank is sitting on up to the surface of the water in the tank. This should get you pretty close to actual head height.
The effects of head combined with the restrictions from your canisters will slow a pump way down.

BTW, nice looking setup.

Thanks for the compliment.

I don't believe calculating the head in my case is that simple. Unlike a sump where the pump has to lift the water back to the aquarium, in a closed system like mine the pump doesn't have to fight gravity, it only has to fight the resistance of the plumbing / filters / viscosity of the water. I can't calculate that easily. Besides, I don't need to know precisely. A ball-park figure will do and then I need a recommendation for a good pump accordingly.

 

[Oreo]

OK, I've been studying pump curves here a bit.

I have 9ft of head. Period. End of discussion.

So who makes good pumps?

 

[dawnmarie]

I have 9ft of head. Period. End of discussion.

Easy friend, before posting a photo you were puzzling over how to determine "head", Now you know.
Don't shoot the messenger.

I must have been asleep when I looked at the picture. Completely missed the closed loop. You are correct, "head" doesn't come in to play at all.

Either You have a significant restriction in the supply/return or your pump is malfunctioning.

Have you considered removing the pump and testing it's actual output unencumbered by the rest of your system ?

A ball-park figure will do and then I need a recommendation for a good pump accordingly.

My preference is Little Giant pumps. I choose the 220v versions when possible to reduce electrical costs. They are slightly noisier than my mag 12 but far more energy efficient.
It's going to be a little tough to recommend a particular pump without knowing the rest of your system information, for example, how large is your tank ?
Turnover rate in a true closed loop system only needs to be high enough to provde adequate mechanical filtration. (See attached quote)

My 240 gallon / closed loop system has a 4X turnover and keeps the tank nice and clean. It uses a Little Giant MD-5 / 220v/ 950 GPH. I have a service interval of 7 days on the cartridges and loose 20-30 % of the rated flow by day seven.

My 100 gallon / closed loop system has a 5X turnover and uses a Little Giant 2- MD/ 500 GPH. I also service it every 7 days and loose 10-15 % of rated flow by day seven. The difference in loss is due to this tank being less heavily stocked.

 

[fox3]

I've bucket tested our 1262 and got a little better than 700gph @ 65" head.

I think that from looking at the pic's you provided, nice setup BTW , those 1" elbows are absolutely killing your flow. Ball park figure for 90° elbows is add 1 foot of head per elbow. Mebbe a bit less for larger diameter piping.

Dannermag makes a good pump that overcomes head. Hy-drive 2100 or 2600