Scubaroo
Contributor
You can have TOO much integrated weight in your backplate/STA. Especially if you're diving wet with a heavy steel tank. The main concern is trim - I was using a 6lb backplate, 5lb STA, and 10lb when full 95LP steel tank - this was 21lb of negative bouyancy on my back. I wasn't horizontal - I was head down! Lowering the tank didn't help - it was just too much weight on my back. Use some common sense when setting up your backplate instead of just using the heaviest gear your can find. I swapped out the STA for a light one, and added some more weight around the waist, and now my trim is fine 
There is also the slight issue of ditchable weight in an emergency!

There is also the slight issue of ditchable weight in an emergency!