Zeagle Zena - Buoyancy issue

[redacted]

While 8 kg seems like a lot of weight, it is fairly clear that you need 9.

 

[Capt.Gene]

If you are looking down at the start of your decent there's a fair chance your more horizonal than you realize, and trapping air in the BC.
If you can get your left shoulder slightly more over and behind you the BC will dump air much better.
IF you can find one to use, try diving with a steel 3AA2250 psi tank, the old 72.
Part of your problem may be coming from the length of the Al 80.

 

[reefvagabond]

There's a simliar thread for your issue but with someone using a Ranger on scubatoys:
Descending Issues in Ranger

I actually have the same issue as you with my ranger (never had problems w/ the same weight and a rental jacket BC), once i get to about 10 feet i have no problems with buoyancy. Inorder to descend I have to go head first, maybe you can try that just make sure you equalize often.