Rena Filstar XP3s leaking air

[Krystle]

I have three Rena Filstar XP3's, all three of them are probably about 5 years old or more. They all leak air into the canister, so that the water level inside the canister when it is running is about 1 1/2 to 2" below the top.

I researched it on the rena website, and concluded that my canister and quick-disconnect O-rings needed to be replaced. So I bought new O-Rings and installed them. The water level was perfect for the first day or so, but now they are all leaking air again.

I read something once about putting vaseline on the O-rings to prevent air from leaking? Can anyone tell me more about this? Should this be neccessary with brand new O-rings? Does anyone have any other suggestions? These are great filters, I would hate to have to replace them all.

[Kronosdelsol]

I would only add white grease to the quick disconnect valves but not to the rings itself. That is how it comes from the manufacture. I think it is only to help with the disconnect latch though.

When I clean my filter and notice air in the top 1.5" of the canister, this is what I do.

1. Turn the unit off.

2. Lift the quick disconnect.

3. Take the lid off the intake tube and fill it with water until it is to the top of the T intersection.

4. Replace the lid and drop the quick disconnect back in place.

5. Make sure the water level in the tank is right.

6. Turn the unit back on.

I'm sure you have tried this before though. I'm also sure that you need to reseat the quick disconnect properly. Maybe check the input and output hoses to make sure they have free range and aren't twisted in a weird angle that prevents air bubbles from getting out.

[T Dawg]

There is a black plug on the motor housing. If it is all the way in the air can build up as you describe. It needs to be pulled out, in my case as far as it can go and still clear the canister. I needed a butter knife to help when Rena support was leading me through it.

With the air gap at the top the motor will overheat, eventually leading to issues.

[Kronosdelsol]

I would also check to make sure that the intake holes are all connected tightly. Sometimes the top most connector that joins with the h at the top lets air in when you are draining the water level below that connection.

Good tip about the plug. I didn't know that.

[Krystle]

I am really hoping it is not the quick disconnect valve causing the problem, as I am always careful to push it in firmly before lowering the lever, and I have recently replaced the o-rings. I just took one of the filters apart and pulled out that black plug like T-dawg suggested, hopefully that solves the problem! I also took took some teflon tape and wrapped it around the connection where the cap screws onto the top of the intake, thinking that maybe the air is leaking in there. We shall see!

[jvision]

Just make sure that no air is getting in thru the hoses. The hose clamps should be tight and the cap on the intake needs to be tight.

If it is on your planted tank, the air in the canister could very well be O2 coming out of solution... slow your plants down and you could solve your problem.