I used the 23mg/228mg pills. The recommended dose is 1 x 23mg Large Dog tablet per 400g of tank water. I have 115 gallons total, so divided 2 pills into 3 doses.
Added an airstone to the DT just in case there was a lot of die off.
Remove carbon or similar media if you use any.
Remove all shrimp, crabs and the like. Expect to see some bristleworm copepod and amphipod death. I removed most snails. The ones left behind were fine and the copepod population recovered.
Mix your crushed pill in warmed RO (microwave) and slowly add near tank flow. I did mine after lights out so the fish wouldn't eat anything not dissolved.
It's recommended to leave it in the DT for 9 or so hours, but I did 12 and have friends who went as long as 24hrs.
Now do a 25% WC and add Carbon. I used Rox 0.8 and left it in for a few days.
Wait a week and dose a second round, WC carbon.
Then wait another week and do the third dose WC carbon.
After week 3 I left the carbon in for a week, then did another 25% WC and another week of carbon. After this I added my cleaner shrimp back to the DT and it died a week later !! But the snails were fine.
So, I'd suggest running carbon for a couple weeks and change it maybe every few days. Follow this up with a large WC