Generally every night. But, they do occasionally deflate and turn into a green "apple", LOL, ant odd times for a variety of reasons.
Unless you are talking about the bubble tips. For some strange reason, the bubble tips on my BTA stay deflated most of the time, masquerading as an LTA rather than a BTA. Quite common with a lot of BTA specimens, and nobody seems to have figured out why.
I have had other types of nems like the condy but never had a BTA got up this mourning and it look like something had suck him dry but all plumped as we speak.
Are you asking about my photos? Those are just of my green BTA. The purple tips are standard character for these, but they are accentuated by the true actinic T5's in the light fixture.
It didn't work for me. I tried everything. The only thing that kinda worked was a spotlight on the nem during nighttime hours. The clowns spent that time in the light close to the nem. In the end it just happened one random day. Suddenly all my clowns were fighting over it.