My bubble counter started leaking again and I lost the best part of half a bottle of CO2 last week. This gave me the perfect excuse to justify some new toys as a 'cost cutting excersize'. The first was a glass TMC AquaGro bubble counter. Just what you'd expect - no chance of leaks and its a small clear bubble counter with a couple of suckers for mounting to the side or back of the aquarium. The second more interesting item was the TMC Aquagrow Power Diffuser 1500 This is a CO2 reactor for use in large tanks that resembles a bong. The CO2 is piped in at the top alongside a fast flow of water. The water flow spins a prop that churns the co2 and water together the outlet is via a tube with it's opening at the bottom of the bong and exit again at the top. this means the CO2 has to go down through the churning water before it makes it out into the tank. This ensures that only dissolved CO2 or micro bubbles escape thus limiting the waste of your CO2. I bought the 1500 for my 220L tank as I wanted to attach it outside of the tank to the Rena XP3. Unfortunately this was not to be. Despite the supposed design for 1500L tanks and 1000lph max throughput the inlet connector is has an external diameter of a mere 12mm approx. It is glass smooth and no raised lip for secure connection. If I connected this outside the tank I'd be terrified the pipe would one day slip off and the entire tank drained onto the living room floor. Even inside the tank the diameter of the inlet was too small to successfully connect it to my filters outlet pipe. Fortunately I had an old 800lph internal filter of unknown brand sitting in the cupboard and by removing it's outlet guide I was able to jam the two devices together. After that it only took a few moments to complete the setup. I was disappointed that the suckers only fit on one side of the bong and the inlet is not adjustable. This left me with rather an unsightly block of equipment to the right of the tank. I hope and expect that some plant growth will sort this out soon enough. The good news is that it appears to work, and silently at that.