# best way to slow canister flow? (cascade 1000)



## jaidexl

It's my first canister, just setup. Would it be best to lower the intake, outflow, or both equally? I guess I'm concerned with which would strain the motor more, if any.

Thanks in advance -J


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## goalcreas

what about using a spraybar or using multiple return points to just slow the current instead of slowing the flow rate thru the filter.

Or if you with to do like you said, I am in favor of slowing both, you can do this with the quick disconnect ball valves that you can buy online or maybe a LFS, some of the canisters have a flow control on which would end up adjusting both equally.


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## vic46

Another option may be to use a rheostat. This would reduce the impeller speed and therefore the water flow rate. I am not sure that this is a viable idea as I am not sure what the long term impact on the impeller may be. Hopefully someone will have the straight goods on this option. You could also try to determine the appropriateness of this option through on-line contact with the manufacturer of the filter.
Vic


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## jaidexl

This Cascade has dual ball valves, I'll most likey be using the spraybar when it's setup (seeding it on another tank now with open attatchment) and will probably use both valves if needed. I suppose either way probably won't make much difference to the motor, but this filter was a PITA to keep primed at first and I'm hoping it doesn't take any little thing to make it lose prime in the future, like not enough intake or something.


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## houseofcards

On my eheim I've always reduced the flow on both in and out equally. It has never given me a problem in almost two years.


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## mott

From what I have read you should only adjust the outflow for the cascade.
I have a 1000 and Ive been doing it that way for 6 months with no problems.
Jaid, the first prime is a PITA but you wont have to worry about that thereafter.
My trick is Ill syphon water from the in and just let the can fill up before starting this way you wont even have to prime with that big button!


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## BryceM

As with all pumps, the inflow should never be restricted. This can create a negative-pressure situation inside the pump. This can result in outgassing of dissolved CO2 and O2 and will cause the impeller to cavitate, greatly reducing its life and causing noise. Restricting the outflow produces no stress on the pump motor at all.

Incidentally, I've found out the hard way that Eheim ball-valves can sometiems leak when they're in a semi-closed position. Maybe it's just a bad valve and maybe nobody else's does this, but it's worth a check if you try it.

BTW, using a rheostat wouldn't work. This would only decrease the voltage, placing an enormous strain the motor. Typical electric motors may be "throttled" by adjusting the frequency (usually ~60 Hz) but this requires very sophisticated electronics - far beyond what is practical for a hobby application. Almost all AC electric motors run at a constant RPM, except at startup.


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## jaidexl

Thanks for that info  I did notice more noise when the intake was closed halfway, so right now it is only 1/4 closed and the out is 1/2. I'll go open the intake now.

My first prime was probably worse because I haven't trimmed the tubes yet, want to wait till it's set up on it's intended tank so the lengths are right on the money. I had to pull the filter out from this particular tank so the tubes weren't looping before it would prime, I also filled the filter compartment at the sink. 

Thanks again for the info, everyone!


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