Filtration Question

[Nexstar]

I just set my tank up for tropicals after having Africans for a few years.
I chose a Eheim Professional 2164 canister filter with heater and decided to use an undergravel filter as a reverse flow system by taking the return from the canister and placing it in the undergravel filters tube pushing rather than pulling water thru. This is not meant to be for biological filtration in the filter bed but rather to keep the Florabase substrat cleaner.
Now the 2164 has a flow meter(ball) in the canitster and I have noted that the ball is down on the red line. I suspect this is because that the flow or back pressure fron not having a spray bar make the system feel reflect low volume and I am sure with the whole bottom undergravel filter as an outlet it has done just that. If you have one of these filters or know a lot more than me (most anyone qualifies here) let me know if this thinking is correct and if I am ok to continue to use it this way.

Thanks
Bob

 

[Lateral Line]

Doesn't sound like a particulaly good idea to me. I would have expected exactly what you are seeing would happen. The substrate is impeding the water flow.

The contactless impellor pumps are not designed to produce a very high pressure as a result the flow through the filter is lowered, reducing it's effectiveness.

Ultimately, the reduced flow of water through the impellor chamber which cools the pump, could cause it to overheat and distort. Not fixable, new pump required. Had that happen once on an Eheim 1008 which I allowed to get to far out of the water.