Maybe worth while to use rain water, collected after it has rained a while to clean the air.
Another way is to make a bed of peat in the bottom of the tank, remove the mops, and remove the peat, and water store every 14 days.
It may work.
I wonder about the sterilization part.
Since the attack in NY, the airport surveilance has gone up, and I wonder if the X-ray machines could do the act.
Do you belong to a killi group there?
If not, join up, and I'm sure it won't be long before you have got juvenile breeders to work with from other breeders.
Now these ones you CAN rely on for breeding.
They will be accustomed to your own conditions, and any probs, you'd be able to discuss with them.
Alan 104