Okay, so my oxygen sealers aren't working. I have an oxygen farm just outside my base, and yet it still isn't working. My base is 15x15 blocks, and is 8 blocks high.
Link the the pictures of my base (And oxygen farm): http://imgur.com/a/nR0Af#0
Link the the pictures of my base (And oxygen farm): http://imgur.com/a/nR0Af#0