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Cathar · 01-25-2004, 01:45 AM

I fed my Eheim 1250 outlet into the inlet of my Iwaki MD30-RZ. Near as I could tell it added close to exactly the pumping pressure that the Eheim 1250 produces at the resultant flow rate that it was pumping with.

It doesn't matter if the pumps are mismatched so long as the resultant flow rate through the system is not higher than the maximum flow rate that the weaker pumps can push in open flow.

The Eheim 1250 can push 20LPM maximum, but realistically around 15LPM after accounting for the tubing and fittings on the 1250. The flow rate through my system with it in series with the MD30-RZ was around 12LPM in the test I did (WW + raidator), which is less than what the 1250 can push in wide-open mode, so it was safe to add it in series. Without the 1250 in series the MD30-RZ was pushing just over 11LPM by itself through the same loop. However, since even 11LPM is more than the Eheim 1048 can push in wide-open mode (10LPM max) then it would've been a bad idea to stick the Eheim 1048 in series with the Iwaki MD30-RZ.

Sticking pumps in series can work well so long as you don't grossly mismatch.

01-25-2004, 01:45 AM	#4
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	I fed my Eheim 1250 outlet into the inlet of my Iwaki MD30-RZ. Near as I could tell it added close to exactly the pumping pressure that the Eheim 1250 produces at the resultant flow rate that it was pumping with. It doesn't matter if the pumps are mismatched so long as the resultant flow rate through the system is not higher than the maximum flow rate that the weaker pumps can push in open flow. The Eheim 1250 can push 20LPM maximum, but realistically around 15LPM after accounting for the tubing and fittings on the 1250. The flow rate through my system with it in series with the MD30-RZ was around 12LPM in the test I did (WW + raidator), which is less than what the 1250 can push in wide-open mode, so it was safe to add it in series. Without the 1250 in series the MD30-RZ was pushing just over 11LPM by itself through the same loop. However, since even 11LPM is more than the Eheim 1048 can push in wide-open mode (10LPM max) then it would've been a bad idea to stick the Eheim 1048 in series with the Iwaki MD30-RZ. Sticking pumps in series can work well so long as you don't grossly mismatch.