Eheim canister filter

[SarahBravo]

Because my 4' tank has a 1.5" wide flat shelf on the long sides (to put sliding covers/condensation trays on I guess) I can only fit the input/output pipes from my Eheim at the ends. At the moment the input and output are at the same end cos the hoses weren't long enough (there's no room behind the tank for the filter, it has to sit on the floor at one end). Does anyone know if it will reduce the filter's efficiency/operation etc if I add another couple of feet to the output so i can get the flow right, flowing from one end of the tank to the other?

Thanks!

Sarah

 

[CathyG]

Hi Sarah

I have a similar shelf on my tank and what I did was use the suckers to attach the outflow pipe to the underside of the shelf. I use an Eheim Pro II 2028 on my tank, and I still have to reduce the flow so extending the hosing a little has not caused any harm. I guess it depends on the filter you are using, but as a rule of thumb if you could make the two lengths (one for each pipe) from the amount of hosing supplied with the filter, then you should not be compromising the efficiency by extending one of them.

As far as I know, the Eheims (excluding the wet/dry filters) have a maximum delivery height which averages about 6ft on filters designed for that tank size.

 

[Lateral Line]

Pipes resist the flow of fluid through them. The longer the pipe, the higher the resistance they create and the harder a pump has to work to drive a fixed volume of water through it. The mathematics is quite intricate, but try blowing through a 2m length of airline, then try blowing through a 100m reel of the same stuff - you will notice a huge difference.

What also makes a difference is the couplings used. Often the coupling piece has a smaller diameter then the pipe, and the two pipe sections fit over it. This creates a greater resistance then the pipe as, obviously, the same amount of fluid has to pass through the narrowing as through the rest of the pipe.

So much for todays lecture in fluid dynamics.

The ideal state is to keep the lines as short as possible. If this is not possible, extend the inlet pipe rather then the outlet pipe, as this one has gravity working to assist you, rather then the delivery/return hose where the pump is working against gravity. Finally, if possible, use a longer hose rather then introducing a narrow junction piece.

At the end of the day, the extra length you are talking about will have a pretty minimal effect.

 

[SarahBravo]

Thank you! I will buy a longer piece of hose for the inlet pipe and chop a foot off the outlet, hopefully the affect will be negligible.

sarah