# Magnum 350 canister has no flow



## midnightpavo

I was cleaning the filter in my MarineLand Magnum 350 canister filter and when I set it back up and turned it on, no water would flow through it. There is absolutely no water coming out. I have taken this thing apart countless times to see what is wrong but I keep getting the same result. I have cleaned out the tubes, I have cleaned every part, everything is in the right place, and the valves are in the correct positions. I am at a complete loss. Please help.


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## Elliott225

Clean the impeller. Could be some crude or the shaft is worn.


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## toddnbecka

Is the impeller running? Unless there's something blocking the intake tube or it's not primed that's the only reason I can think of for no flow. I've had problems restarting eheim canisters because there was air trapped in the impeller housing, but they have top mounted motors.


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## midnightpavo

I know the impeller is working, I have tried to see the water flow inside without filter media and there is a strong vortex. 

What do you mean by primed?

The filter was working before, only with a very low output rate.


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## midnightpavo

Update: I checked the hoses and the output is full of air, and the intake is half filled with water and dead still. This means that there is no crossflow at all. Its not sucking in or pushing out.


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## toddnbecka

Primed means the intake tube is filled with water all the way to the filter. 
Is there air trapped in the impeller housing or motor? Have you tried turning the filter on its side or even upside down while running?


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## midnightpavo

How would I fill the tube with water?

I just tried turning the filter a bunch of ways and all it did was get louder.


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## midnightpavo

Update: I started playing with the valves and now have a tiny amount of flow. some water is trickling through the tube but it still wont fill up with water.


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## toddnbecka

Did you fill the canister with water before attaching the hoses? If so, then pour water into the ends of each hose to fill them completely with water. That should eliminate most of the air in the filter, and any remaining should be pushed out when it runs.


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## midnightpavo

Yes I did. I hope I can fill them with water. The entire setup is old and fragile. Detaching the hoses will be difficult.


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## midnightpavo

I was able to completely fill the hoses with water and I got about a second of high flow then it went back to trickling.


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## toddnbecka

Is there visible wear on the impeller or shaft? Does water siphon freely through the hoses?


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## emc7

The motor is humming and the impeller is turning? If you just run in open on the counter, it spins?. Check for clogs in the internal black pipes there is a bend under a black plastic tab thing on the lid that loves to grab plants. Check all your gaskets, o-rings etc. If air can get in the system it will and the motor won't be able to pump the water out. Put grease on the o-ring and make sure it is in the right place. Try it will no media or just the pleated filter to see if you have a clog in the basket. Are all the hose clamps/rubber bands in place? Check for cracks in the lid and clear plastic tub and bad seals by drying the outside off and then turning it over. Fill the hose to the quick-connect valve with a funnel, then close the valve, and turn it upside down. If it goes blub and more air gets in, you have a leak somewhere. Try a new o-ring and/or grease (white silicone) on the O-ring. If you find a crack, you can replace the piece (I had a lid with one hose attachment point cracked) or possibly seal it with epoxy.

If the motor is good and case is good, check the hoses for splits.

The motors can die, too.

Oh and impellers can seize up. Crud in the well, a bent impeller shaft (replacements are cheap), a black erase tip that's come off.


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## Elliott225

To see if you got free flowing water try this. 

Put the intake tube in a bucket of water. Put the outflow tube in another bucket that is lower than the first. Without the motor running you can start a siphon. No blocked tubing the flow should be strong. Once that you have proven that, re-fill the buckets and turn on the motor. Then you should have a more forceful flow out. If not...check the impeller. 


The impeller may be (probably is) scored on the black part. You will be able to feel it. The impeller shaft will have scoring on it to. You can get new parts. Try to find a ceramic impeller shaft. They don't wear out. Also, be sure the little black rubber plugs are on both ends of the impeller shaft. Those little plugs keep the shaft centered so the motor can turn it. Good luck.


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## midnightpavo

Water is flowing through the tubes and the impeller is working for sure. I'm positive about that. However I thought of a possible issue. There is a bio-wheel attached that has never worked. Its connected to the outtake by a 3 way connector. I tried filing that tube as well with water, but it didn't work.


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## Elliott225

I hate those bio-wheels. Have a HOB filter that uses them and they caused issues. Sometimes they are moving, sometimes not. One turns the other doesn't. Finally just got rid of the wheels.


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## toddnbecka

Biowheels are a gimmick more than an actually useful component.


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