leaving for a month

ok granted that i will be leaving my fish in a friend's tank. if ill leave my tank without equipment running, will that kill the bacteria in my LR? and what would happen with my sump if there's zero flow?

 

I don't recall how large your tank is but I would try this...
No lights on the main tank
Glass cover on the main tank to limit evaporation
Timer for lights on your refugium if you have algea in there.
I would overfill the tank a bit with fresh water dropping your salinity a bit. As you get evaporation the salinity will rise to normal and possibly be a bit high by the time you get back.
It is important to have a rough idea of how much water you will lose to evaporation per day (or week) so you have an idea that your level won't drop so much that your return pump sucks air and burns up. If it looks like this would be the case, you'll need someone to come in at least once while your gone and add some top off water.
Skimmer off but maybe leave powerheads running in tank.
Being gone for a month I would worry that the bacteria on your rock might not survive without a food source so you could throw a dead shrimp in there before you go. This will of course cause your tank to cycle but the cycle should be done by the time you get back in a month. (If you have a lot of life on your rock, you probably don't want to do this for fear of killing it off with the cycle. On the other hand, lots of life on the rock would probably keep your bacteria going without resorting to the dead shrimp).

 

keep your LR in a bin with a pump