Hi Punk,
I've also moved your post to a new thread, just so as to keep the topics separate - I hope you don't mind
So, what do I do to protect my system from Eskom's power cuts?
Some time ago (fortunately for me quite long before the load shedding...), I decided that the risk of losing all my livestock due to a power blackout was just not acceptable, so I bought myself a 7.5KVA Honda powered petrol generator with voltage regulation. I also have a 1.5KVA UPS coupled to the electronic controllers, and also powering one of the Tunze power heads. So, if power goes off, the UPS provides some initial water circulation until I (or most likely the wife) can get the generator out of the garage and powered up.
The generator is then coupled via two leads, one supplying power to the tank, and the other to some critical appliances in the house. At the tank I run all the pumps, the controllers, the O3 generator and Berlin skimmer, and 4 x 36W PC lamps, but not the heaters, chiller or MH's. The generator does have sufficient reserve capacity to also run two of the heaters, if need be.
For the short to medium term, it is essential to have at least some water movement in the tank, with second importance being to keeping the water temperature stable - lighting is not important at all, and all corals can survive without light for quite a few days.
For many years before I bought the generator I relied on a simple 12V bilge pump, connected to a deep discharge 12V battery, to provide circulation from the sump.
Hope this helps some...
Hennie