[teo241]

Help me understand something please.

I had the unfortunate luck to come home to a seized vectra L1 (using as a return pump).

I replaced it temporarily with an eheim 1262 pump -- rated at 900 gph. When running the eheim the flow meter on the return gave me a reading of ~560 gph. (a head loss of about 48%).

I just plumbed in my replacement vectra L1 pump rated at 3100 gph. The same flow meter on the same return reads 830 gph. (a head loss of almost 75%).

The vectra is calibrated in return mode and is running at full speed. Its the same return plumbing. Even if the flow meter is inaccurate (which I doubt) this suggests a huge difference in head loss as it would be inaccurate for both pumps. For what its worth, the previous vectra L1 gave me a max reading of ~880 gph.

Any ideas of why the difference is so much greater with the more powerful pump?