[Cranky When Wet]

Really good question cwatkins!

When I started my Nano tanks I knew that power outages would be a very real danger. Here's the thing: I routinely shut down pumps for feeding on both tanks for up to half an hour each day. Since these systems are relatively "low tech," I use my iphone as a timer and restart when feeding is done.

My rational for this practice is based on my travel time from LFS with new livestock (bagged without additional oxygen) to my home.

What's confusing is that I've been told my 120 gallon FW tank would lose enough oxygen in four hours to endanger life.

The worst crash I've ever seen was when the SW nano's (6.5 and 8gal respectively) went without pumps for what I estimate as eight hours. All copepods were killed; a couple bristle worms were dying; one nassarius snail died; a couple hermit crabs died; but, all corals were revived with flow boosted to twice regular rate.

There seems to be a correlation between size of life and it's ability to endure low-percentage oxygen in column... at least, this is my guess after observing my fiasco...

The hardest part of recovering both Nanos was montitoring resultant nitrite and nitrate spikes. Sg and Potassium values were also headaches as I had to do WC's every day for almost two weeks.

Uh yup, I now have a whole-house monster generator as well as two, more portable power supplies.... Methinks power outages are yet another reason beginners like myself are encouraged to start with larger tanks. The only reason I dared do SW nano's is decades experience tending FW life and an ability to read what the animals are telling me.

Does anyone out there have specific data i.e. how fast oxygen is lost by gallon??? preferably with knowledge of oxygen/water ratio/percentage point at which even small life is in danger??????

How does air/water surface contact area impact rate of oxygen loss?

And, could there be any benefit to having a solid cover on a tank to contain oxygen during emergencies (as in biocube-style tanks)?

Bunny

p.s. just spent ten days in Surrey/Langley and have to say you live in a beautiful place