Tank Size and Weight AL80 to LP85

[d_frag]

I've been certified now for a few months and gotten in a half dozen dives. All of them have been with an AL80, so I have my weighting and bouyancy fairly sorted out with that tank. With the AL80 in Northern California I need 36 lbs. It seems to be a lot, but I've worked that down from 46 lbs from when I started with open water. This weekend I have an opportunity to dive with a steel LP85.

From what I gather through the limited search I've done, the AL80 starts slightly negative bouyant (-1.5, give or take) and when near empty it is +4 lbs (give or take) positive bouyant. The LP85 starts neutrally bouyant, and when near empty is roughly 6 lbs negatively bouyant. Given that, should I think about reducing my weight 4-6 lbs? I would really not want to feel like a boat anchor becuase it is a struggle to keep good trim and bouyancy. Thoughts? Am I in the right ball park?

thanks

 

[Paladin]

I think you have the LP85 backwards. A tank cannot end up heavier at the end of a dive.

 

[Colliam7]

All of them have been with an AL80, so I have my weighting and bouyancy fairly sorted out with that tank. . . . This weekend I have an opportunity to dive with a steel LP85. . . . should I think about reducing my weight 4-6 lbs? . . . Am I in the right ball park?

Yes, based on the nominal buoyancy data for an AL80 and an OMS LP85 (with the correction noted by Paladin). I would probably drop 4 lbs to start, then try dropping 2 more on a second dive, to see if you can do it.