Can Botania Mana be stored in a Railcraft Tank?
Actually there is a way to use minecarts to move a lot of mana - and you can do it under your current base fairly easily.
I am not on minecraft at present so item names will be exchanged with a rough description in some cases.
You place a mana spreader with the lens that allows sending mana through blocks next to your current mana pool('s), aim it down to a mana pool in an underground room. Then make a tunnel to an room under the area you need the mana and place your rail to that room where there is another mana pool (or more) and a mana spreader pointing up to a mana pool in the required room (again with the lens attached). Use mana loaders to fill and empty the carts at each end. The tricky part is to place a redstone comparator at the destination end that powers the rail only if the pool is below a required level AND using detector rail and AND gates and timers to power the rail off so that the mana has time to load and unload.
I used this in DW20 1.7.10 - I would also point out that I chunk loaded the entire area.