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Discussion Starter · #1 ·
Guys I have an eheim canister (dont remember the model) and every time I have to shut it off it loses its prime and is a pain to turn back on. It seems the issue is with the intake bend. When shut off it loses that suction and air gaps the "U" at the top.
I have though about hooking a valve at the base of the intake to keep the water in there but Im not sure that would be fool proof.
Is there some type of trick keeping this things primed?
thanks

I am curious because Im cycling that 55 Im working on and have to do a large water change tonight or tomorrow since the water is getting a bit ewwwwwwww

Im actually thinking of hooking a Y with valves on the output when this is set up so when I want to do water changes I can divert the filter output to a hose and leave it running to use the filter itself to siphon the water out.
Anyone ever try this?
 

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Can you tell if the air bubble comes up from the canister to the "u" or does the air bubble just form in the "u" without coming up from the canister? (Assuming you have hoses that you can see thru).
I ask this because if the bubble just forms in the "u", I suspect you have a crack or loose connection on the inlet pipe. There must be some way from the air to get into this point. It can't go from the surface down to the intake screen, then back up.

If you can see a bubble travel up the intake tubing from the canister, then I would suspect something is leaking air from that end. No knowing which filter you have makes it a bit more difficult, but, regardless which you have once you close the valve(s) near the filter no air should be able to enter.

As a test, try shutting off the valve(s) just before you turn off power to the filter. Does this help with the air bubble issue?
 

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Discussion Starter · #3 ·
Can you tell if the air bubble comes up from the canister to the "u" or does the air bubble just form in the "u" without coming up from the canister? (Assuming you have hoses that you can see thru).
I ask this because if the bubble just forms in the "u", I suspect you have a crack or loose connection on the inlet pipe. There must be some way from the air to get into this point. It can't go from the surface down to the intake screen, then back up.

If you can see a bubble travel up the intake tubing from the canister, then I would suspect something is leaking air from that end. No knowing which filter you have makes it a bit more difficult, but, regardless which you have once you close the valve(s) near the filter no air should be able to enter.

As a test, try shutting off the valve(s) just before you turn off power to the filter. Does this help with the air bubble issue?
what happens is the suction stops and the water just falls back into the tank on the tank interior half. This cavity in the hose causes the air gap and stops the pump from pulling the water from the tank. I end up having to mouth siphon output the canister to get it started again.

I know there is no leak and I have actually replaced all the hoses with new ones and metal hose clamps. I never liked the plastic compression style ones that came on it.

I THINK its the 2215, pretty sure
 

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The 2215 with the green preformed intake? I see indications there may be newer intakes when I check online manuals. For the old style that I associate with the 2211-2217 Classics, I would check that there is not a small crack letting air into drop the siphon. It is reasonably easy to tighten the metal seals too tight and crack the plastic on some things. I've also found myself working too hard and making various plastic fittings fold inside the tubing and this can form a channel for leaks.
If there is a newer intake using the segmented style like 2075, etc. (grey plastic) there may be a fault with the O-rings that join the segments together. I created a problem on mine when trying to head off trouble. I wanted to use some petroleum jelly (Vasoline) to lube things so pried the O-ring off with a screwdriver. Wound up nicking it and making it leak. Did not leak water but did leak air to drop the prime.

About the only way to go for me would be to look very carefully at the setup on the intake. first suspect the joints and then look all along the length of both the tubing and the intake. Squeeze the tubing to look for cracks that don't show very easy when it is round? Things have a nasty habit of holding water but leaking air at times.
 

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Discussion Starter · #5 ·
thanks Ill give it a shot but I dont think I Cracked anything. Ill try to look but the more i researched this filter online its a pretty common issue with it. I just thought someone may have figured out some tricks. Its almost like after the water drops from the bend the pump doesnt have the pull to suck it back up. I have to manually suck through the output to start it, then its fine.
I know my buddies canister has a pull pump for priming and he loves it. I was just on amazon looking for an inline prime pump for this.

Amazon.com: Rubber Pump Hand Primer Bulb 10mm For Boat Kart karting Cargo Marine Fuel Diesel: Automotive

Ill keep looking for something until I figure it out. but I think if I set up my Y and leave the canister just running all the time even during the water changes I should be fine.
 

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One point to question is WHEN you start the pump. Do you wait until the water is fully up to normal level and then start the pump. If not that may explain why it doesn't draw right as the pump is designed to be very light power. One way to make the overall power consumption lower, which is a much higher priority many places than in the US. We tend to ignore things like that.
I'm assuming the end of the intake never rises above water level during changes? That would lose the prime for sure.
 

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Discussion Starter · #7 ·
One point to question is WHEN you start the pump. Do you wait until the water is fully up to normal level and then start the pump.
possible. I actually dont have the tank 100% peaked right now. Only about 1/2 to 2 3rds because Im still technically letting the plants all root and such. Maybe I should just fill it but I didnt bother because I planned on using the water from my 30 to top it off when I did the change over.
 

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possible. I actually dont have the tank 100% peaked right now. Only about 1/2 to 2 3rds because Im still technically letting the plants all root and such. Maybe I should just fill it but I didnt bother because I planned on using the water from my 30 to top it off when I did the change over.
I might say this is a sure problem on restarting. Normally the water siphon going out and coming back will have the water in both tubes at the same level, then when we start the pump it only has to have power enough to boost the water high enough on the output for it to move up and over the tank rim. When the water level is lower, it probably does not have the power to do it.
I would suggest trying it with the tank nearly full and see how it goes.

One of those tradeoffs of good economy is that we do get less power. We could use higher power pumps but then we would pay for it in electrical use running 24/7. Eheim pumps use like 17-18 watts while US made may use as much as 56 watts. Over time , there is a difference.
 

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how far below the fishtank is the canister?

I have 2 eheim canisters about 15 inches below the bottom of the tank, never have to prime them. sometimes i even use the intake hose to drain water from the tank when i do water change and clean the filters at the same time.
 
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