I use Antiformin S, diluted at 30cc per gallon, for all my sterilising, and have never had any problems. I keep a bucket of it on the sink for thermometer, hydrometer, cask taps and tops etc., and an old 5 gallon plastic FV of it underneath for larger items. I use 1 litre Robinsons Squash bottles, and submerge them in the old FV for a few days, then empty them, and without rinsing store them upside down in a cardboard bottle carrier until needed. A quick rinse, then fill via a small bore pipe from the bottom of the bottle, and Bob’s your Uncle.
Antiformin contains Sodium Hydroxide, so treat it as an enemy and were rubber gloves when handling the concentrate.