I add Grapeseed Extract to my bong water. Just 3-4 drops Keeps the resin from climbing up the sides, stays in the water, while acidifying the water keeping it sanitary longer. Exact same thing as RezBlock, but way fucking cheaper.
I read something somewhere about putting coffee in a bong lol. Heard it helps the THC along. Don't remember where I read it but it sounded interesting. I haven't ever tried anything in my bong but water tho.
I tried mountain dew once.... It was not bad. I don't even drink Mountain Dew, but I've always thought it did taste good so that probably helps if you like it to begin with. I want to say I've tried something else once too but I don't remember right now. Anyways, water in the end is the best