1. Use Kalkwasser (lime water) in reef tanks to maintain calcium levels and   alkalinity.

2. Treat tapwater before using it in aquariums. It contains harmful chlorine

3. When cleaning cycled aquariums, keep some water in the tank and avoid a complete overhaul. Bacteria beneficial to fishy environments settle at the bottom.

4. Slope gravel so that its highest level is toward the back to give an aquarium an ascending-into-the-horizon look.