low flow on 2213 Eheim ??

[plateletboy]

Hi there,

I've been a bit worried about the flow on my 2213 recently as it has seemed a bit low, even after a total clean of media, so I 'measured' low long it took to flow 1 1/2 L - and it was about 30 sec which means its only pumping about 200 lph, not 350-400 lph as the specs suggest.

It sounded like it had been sucking in air for a while so i changed the main seal, but its still on low flow and still leaks air into the top - but never leaks any water out.....?

Anybody have any ideas? there are no air stones at all to go up the inlet.
thanks,

PB

 

[sub.42]

The only things that would reduce flow on your filter are as follows.

1. Blocked or partially blocked media.
2. Unit drawing air from unions. (airlock)
3. Unit drawing air from pump body seals, or any fitted check valve. (airlock)
4. Increased clearance between impellor and housing, or impellor motor fault.
5. Decrease in head of water.
6. Bent or distorted hoses.

Is your pump below your tank, or is it level? If it is level with or slightly above the level of the bottom of your tank, that would reduce the performance aswell. You must also remember that filter manufacturers state figures for the filters under absolute perfect conditions, and you may not always achieve that at home.

The other thing to remember, is that if you dont't prime the filter properly in the first place, it won't work well either. I suggest you re-check all the seals and water connections again, and see if you can see air being drawn in on the filter suction line. If that is the case, you have an air leak, and you have to plug it.

Happy hunting....

Sub.

 

[Tolak]

If it has been running for a while the hoses may be partially plugged with algaeish gunk or other debris. Mine tend to do this & have to be cleaned out a couple of times a year.

Tolak

 

[plateletboy]

Marvellous!!

thanks for your replies Sub/Tolak......

No.5 decresed head of water !!! Does the pump like to be under 'pressure' from having the tank well above it then??

this makes sense..... My tank is quite low level - maybe only 12 inches off the ground, so the pump's head is almost level with the bottom of the tank....... why does this reduce flow? i always thought pumping head was based on the maximum height you pump could push?

or is it a case of if the water pressure inside isn't high enough (from being below the tank) air will leak into it?!?


PB

 

[konrad05]

Gravity

Same reason why when you drain your tank with a hose, the water moves faster as you lower the tube down below the tank

 

[plateletboy]

Konrad,

that makes no sense whatsoever. If gravity pull water into a filter by a siphon, there is just as much force against gravity to push it back up to the tank.

I was wondering why eheims like to be under this pressure to pump better.........

PB

 

[sub.42]

Well, all pumps pump better if they have a head of water pushing on the inlet side. Its simple physics.
If there is already a force acting on the pump low pressure side, it will make the movement of water by the impellor easier. As has already been said, you have created a syphon effect before you even start.
These little pumps are nothing compared to what I work with everyday. I work in the water treatment/carwash industry, and we are talking BIG tanks, and even bigger pumps.
My equipment can move several thousand litres around in under a minuet, and they all use a very basic form of fluid bed and carbon filtration to scrub the water clean after it has been used. Hey! we even use RO water to rinse the cars with, so you don't get spots on your cars after they have dried!!!!!

Dont worry too much about your Eheim, most pumps of that design are much better at pushing water than sucking it up, so always try to ensure that you give it half a chance by placing it as low as possible under the tank level, and keep checking it for air locks. Have fun....

Sub.

 

[freddyk]

Keep in mind that specs the manufacturer quotes is based on an empty filter. The flow is never as high as stated once media is placed in it.