fluctuating water level in drop checker?

[fourmations]

hi all

just curious, what causes the water level to rise in a drop checker?

i use the usual chameleon shaped ebay job
and when it goes in the tank the air/waterline is right at the mouth
and it gradually rises, takes days....

whats it all about?

rgds

4

 

[glenn]

the only reason i can think of is if the air traped in-side it is escaping from some where.
very un-usual though

 

[aaronnorth]

the air is diffusing slowly into the water

Simila rto a CO2 bell diffuser which the tetra optimat comes supllied with, not very efficient method though.