yeah im in the same boat too, i think i will drain the tank to half way and take out all the gravel, i will have the sand all prewashed and ready to go in, turn off heaters and impellers and all that fun stuff lol. then scoop in pool filter sand with my fish still in the tank, then add some more water so its essentially a water change. i dont think it will harm bb too much considering i have a rena xp2 canister with tons of surface area for bb to grow in it. it will be a quick change and less stressful on the fish then scooping out and acclimating and it would be far quicker.
i have hardy fish so im not worried but with more fragile species i would be careful.
i have hardy fish so im not worried but with more fragile species i would be careful.