I'm in a bit of a jam. I'm down to the last few drops of indicator fluid for my drop checker, making the colour virtually unreadable. There are no local suppliers, and mail order would take too long to arrive before any damage is done by incorrect CO2 levels. There is a Pets At Home just up the road, and they sell liquid Ph tests. Could I use this in my drop checker, or does it need mixing with 4dKH water etc? If so, is anyone around Salford who has some handy? 🙂