Switching from AL80 to AL100

I'm going to Cancun and last time I did a Warm water dive I had an 80cf which I recorded my weight as 12 pounds. Approx how many pounds should I drop for the 100cf? I did the math and it sounds like 1 pounds??? Is my math off?

I dive steel tanks at home and I love them. I wish there are more places in Cancun with Steel tanks.

hqduong:

I'm going to Cancun and last time I did a Warm water dive I had an 80cf which I recorded my weight as 12 pounds. Approx how many pounds should I drop for the 100cf? I did the math and it sounds like 1 pounds??? Is my math off?

I dive steel tanks at home and I love them. I wish there are more places in Cancun with Steel tanks.

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That depends on whether it's a Catalina or Luxfer AL100. The Catalina is pretty much neutral when empty while the Luxfer is pretty much like an AL80 at 3 or so lbs. of buoyancy.

This may provide some help there: Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Going from an 80 to a 100 i tend to add 4 pounds of lead. So i wear 12 pounds with an 80 and 16 pounds with a 100.

The reason i add lead is because even though you are alot heavier at the start, by the end of the dive the cylinder is very buoyant so i need the extra weight to keep me down towards the end of the dive. I generally calculate there is about a 6 pound swing going from full to 3 quarters empty on a 100, this means if i weight myself to be neutral at the start of the dive i will be 6 pounds light at the end of it!

I generally add 2-3 pounds for the AL100's I use in Cozumel. I couldn't tell you which brand they are - they are worn a bit and honestly I have not checked. As said, they are heavier at the beginning of a dive and and more bouyant at the end. At the end of the dive I usually have no or very little air in my BCD the last 10 to 15 feet including safety stop. If I go higher than 10 feet there is a chance I can hit the surface so I have to watch my depth. If you are concerned about that then go a bit heavier.

The weight also depends on what I have with me like a camera which is worth 1-2 pounds (negative). Also note on warm water dives, I am not wearing wetsuit or may have a 3mm full sleeve jacket so I have to adjust for that at shallower depths - it's still new. So with the jacket I want enough weight to get past the initial descent and not have to fight to stay down on the final ascent.