I recommend that you format your fluid cells in the Cell workbench, so you have a cell for each fluid. Keep these in a Drive with high prioity.
Keep a couple of unformatted cells for random fluids in a Drive with low priority.
Lastly stick a Fluid Storage bus on a Fluid Void, set it to medium priority and filter it to the fluids that have a chance of filling up their formatted cells.
Control the acquisition of fluids like water and lava with Fluid Level Emitters.
Now all your fluid storage is completely automated. Your storage will never fill up with "junk" fluids, but you always have a stock of every kind.