Tap KH is 3 also. Have bought some distilled water from the garage today so will set about making some 4KH water this weekend.
Apologies about the KH misunderstanding, I though it was at least in part to do with the KH of the tank water.
The bits were: small piece of 6mm airline, a 6mm straight airline connector, and airline clip and suction cup, and the glass bottle. My mum gave me a set of 10 scented oils in mini bottles for Christmas last year, with really tight plastic stoppers. I first tried to make a hole in the plastic stopper so I could wedge a piece of airline through it, but it would not fit for love nor money (and trust me, I tried both LOL!) and then I thought a connector might do. With the airline over the end, if I push it into the neck of the bottle it makes a completely watertight seal, then I just clipped it onto the airline clip. The whole thing is about 2 inches tall from connector to bottle base. And I have 9 more bottles that I could use! (Although only 2 more clips, and no more straight connectors...)
To be honest, I know for a fact there is going to be very low CO2, this is just so I can be depressed about how low! lol. I can't afford a pressurised system, and won't be able to for a good few months, and if you're right Coley, that yeast is unfeasible on a tank the size of mine, then I'm stuck with low CO2 for the time being.