I do remember the first time I made up the bottles. The entire house had to be sterilised. Nothing was safe. Everything bleached. Toilets, stairs, kitchen, counter tops, table, dining room, bedrooms, floors, cupboards, chairs, legs of table and chairs, windows inside and out , mirrors polished etc. It was going to be a fucking sterile environment if my child was going to have a chance to survive.
THEN the new bottles were washed in hot soapy water and after about 5 minutes per bottle, they were reverently transferred to the steriliser. Kettle had of course been boiled in preparation for this astronomically important chemical experiment. Timer was set to 20 minutes precisely so that the boiled water could cool sufficiently. The newly sterilised bottles were laid out and I went to the scooping powder scoops into the bottles phase. Given the risk to life of me losing count, two independent auditors were present to verify my count of scoops into each bottle. Then of course, the transfer of water into the bottle began. I was tremoring at this point with the sheer gravity of this event.
I knew a LOT about solutions. The miniscus had to be eyed up in full light, at eye-level of course, lest I perhaps over dilute or underdilute.
Bottles then had to cool further before being transferred to the bottom shelf of the entirely bleached, rinsed and then sterilised fridge.
I relaxed after a while.