Is it normal for a tank to be too tight to stay down over the spike. I push it down and it pops right back up. I didn't have this problem with the 5 blue tanks that came with it but i just bought 2 boxes of 5 clear. I have tried a couple of them and they do the same thing. It seems the gasket section is really tight and pushed the tank back up but the juice seems to flow if i hold it down.