Thanks. The tank on the left is 60cm x 45cm x 45cm and the tank on the right is around 40cm x 28cm x 25cm. I am running a red sea turbo and a 2 litre coke bottle reactor for co2. I set up both tanks a couple of years ago before I planned to have plants so the substrate for both is just 1-2mm river sand which I have added 25 or so clay balls for fertilization.