XP2 Making Bubbling noises

[Marconis]

I recently changed my PFS for moon sand, and ever since my XP2 has been making water bubbling noises. I tried tilting to see if air would come out but nothing did. What's going on?

 

[Jchillin]

Did you check your intake hose? I mistakenly allowed mine to get a kink in it and every now and then it closes just enough to restrict the flow and produce a gurgling sound.

 

[Marconis]

I took the top off and then put it back on and the sound stopped.