54g reef tank

[michika]

Mix your water outside of the tank, unless the tank is completely empty, no sand, no rock, nothing. If you want to add water after you add rock you should do it pre mixed. Mixing in salt and water in a tank with liverock could kill off your beneficial bacteria and any pods that may have shipped with your rock because of swings in salinity.

If you want to do 10% I would say it should be of the total volume of the system. It doesn't have to be exactly 10%, you could always just go for two 5g buckets, or if you have a separate tank set up for mixing and preparing salt water, then go that route.