You need to slowly increase the dose over several weeks. Personally, and especially with a smaller tank, I would recommend dosing kalkwasser saturated vinegar, as it’s easier to titrated the dosing (not such small amounts) and because it won’t affect the PH (because of the kalk). If you want specific instructions (that I got from @RandyHolmesFarley), feel free to ask. But if you stick with the nopox, I would follow the dosing chart for Vodka (as they are roughly the same potency):
Dosing 2ml right off the bat is a lot for a small tank, you want to start much smaller (can create a bacteria bloom). If you decide to go with Vinegar, you will dose 8x what this chart calls for. You need to dose it daily for it to work though, it’s not something you dose periodically, and if you ever decide to stop, you need to titrate the dose back down. Also, you’ll want to run your skimmer on the wet side (it will be pulling out some of the bacteria that are holding nitrates as biomass). If you have any questions, feel free to ask.
Oh, and to answer your question, yes it smells like solvent, it’s basically vinegar and ethanol mixed, but if your titrate the dose slowly it’s completely safe.