Sorry, I’m not sure what “2 tunk” refers to in a Jain context. In Jainism there isn’t a standard term or practice known as “2 tunk” for water.

If you mean a specific scripture, rule, or local custom, please share the exact source or wording. In general, Jainism emphasizes non-harm to all living beings, including microscopic life in water. Many practicing Jains prefer filtered or boiled water to minimize harm to microorganisms, but exact practices can differ between Digambar and Śvetāmbar traditions and between laypeople and monks/nuns.

If you can provide a bit more detail about where you saw “2 tunk,” I’ll explain it precisely according to authentic Jain sources.