No, this is an absolutely horrible idea. The recommended dose of 25g is to ensure that the lethal dose is already absorbed in case you throw up. SN in doses as small as 2g is lethal for someone of average weight. A previous user tested 2g of SN, bear in mind he was a med student and knew that he'd have to be rushed to the hospital. From his recollection, if he hadn't been administered methylene blue, he 100% would've died. SN is not something you're meant to "Try" unless you know that you're fully prepared for the consequences.
If you want to test your SN for purity, use an aquarium test kit. If you want to overcome your SI, well you're just going to have to sit down and try to internalize your thoughts and why you want to CTB in the first place. DO NOT toy around by actually consuming SN.