You didn't answer a question I posed to you awhile back ... Is this going to be a 1 day transfer? If not, it'll be a piece of pie, or easy as cake ...
There are others here who I hope chime in as I'm no expert ...
Ok well it seems that the safest is adding sand after the fact. A couple questions regarding this method:
1. How do I pour the sand evenly out of my bad (hand?) without getting it all over my LR and corals?
I use a small measuring cup with the pumps off. Bucket full of sand wet with some tank water nearby and scoop with said cup. Then slowly dunk the cup in the tank 'till it's submerged. Go near the bottom and tip the cup, pouring as you go. Gravity will do the rest. It will literally 'pour out'. A turkey baster after the fact is good to clean sand off stuff.
2. How do I get the sand in all the tight spaces (caves, overhangs, tunnels etc). As above. Pour it near the space and the volume will fill it in. It will find it's way into spaces. Use your hand to push it around, wave it around. You'll be surprised how easy it is.
3. How long do I have to wait before I can start adding sand?
I'd personally wait a couple weeks. Others may tell you different. After adding sand, the system will be cloudy overnight. Changing socks will help. Don't panick. It will eventually clear the next day.
4. Can I add my whole 1” sand bed at one time?
If you're starting out Bare Bottom, I don't see why not. As long as the new sand is clean and 'new'. Rinse the heck out of it in (hopefully) a laundry tub using a small (2g) bucket. Rinse a couple gallons at a time with the tap running to 'overflow' the bucket. Swirl it around in the bucket with your hand, pour it out. Repeat many times. You'll be surprised how 'cloudy' new sand is.
You'll never rinse it 'clear'. I do 5-6 rinses per 'clump'
5. What bacteria additive should I add to the new tank?
My suggestion was Seachem Stability. Follow the bottle directions.
5ml/10g tank water on day one. Then 5ml/20g tank water each day for 1 week. This is to get you over the Ammonia hump. Any use after 1 week is a waste of money, unless you have am Ammonia problem.
And you're only doing this if you're adding livestock. It will not seed the tank.
It's only meant to combat Ammo from livestock.