Why I asked is, this morning my air compressor tripped off in the power box and i wondered why the fish didnt look happy and were huddled together. Then I saw it. The compressor was still warm - so was probably off for an hour or so.. I switched it back on again.
When we had the load shedding our power used to be off for hours, every other day - they always had problems getting it back on again.
I like that battery idea to keep the oxygen.