both my intakes didnt have valves when i got it. with one i use a calcium reactor valve and the other i cut a 3mm piece of the tube off, then cut the 3mm piece long ways, folded it and inserted it into the existing tube reducing the tubes diameter by about 1/2. that certainly helped, you could literally see how much finer the bubbles were.
scatman - i'll check it for you when im over next to pick up those pods