Gas pipes which have ambiguous flow directions destroy gas.

The lower pipe over the valve slowly catches all of the gas flowing into it.
After it hits 10 kg another packet slowly starts catching more.

If you could point out where exactly this gas is being eaten that would help a lot, because I can't find it.
 

in corners gases congregate into 10kg , you can use straight pipes to pump any small pocket, but it wont change the amount.