Just had three days of noisy grief from my FX6. I mean proper, intolerable racket meaning it had to be switched off. Tried to fix it for three days with everything from rearranging and removing media, shortening hose lengths, tightening everything, but things just got worse. Eventually, it was only going 15 minutes before that horrendous trapped air and sloshing sound kicked in, after previously going about two or three hours (you can keep switching them off to purge the air, but it's a bit of a pain).
Eventually managed to isolate the problem to the intake pipe fitting at the aquastop valve, which couldn't be tightened to stop air getting in, despite trying it with two jubilee clips as tight as they would go. So I gave up and, as I had a replacement FX6 on the way, decided to wait and just swap them over. But then I noticed, while rummaging for a spare FX6 intake hose and realising I didn't have one, that the 406/405/306/305 hose is a very similar width, so decided to try it.
At first it looks like the rubber stop won't go into the aquastop, but after five minutes of pushing like a good 'un, it was as tight as it gets and all the way in
. Two more jubilee clips and it's as secure as anything.
Now here's the weird bit. That fitting is actually BETTER than the FX6 one
, because the lack of tightness on the real FX6 hose seems to work it loose after a while (11 months for me) and let air in. I can hardly hear the filter running now it's so good, and I just had to put my hand in the tank to check there was an output. You have to improvise with the strainer and dispense with the plastic sleeves, sticking the 406 hosing minus the rubber bung straight into the top of the sieve, but it fits great.
Wish I'd used one before...