I'm still setting up my tank and learning about what to do best before buying any fish. When I replace the water, I would have to use the same sink I do washing up. Is it true that if any washing up liquid gets into the tank it can kill the fish? I'm already careful to try to wash away any cleaning chemicals from the sink before I use it for anything to do with the tank, but thought I would check up on the facts on here too. What can you do about limescale? Can you only scrub it with water? If you want to wash things from the tank, is there any kind of safe chemical, or can it only be water?
Re: Advice on cleaning chemicals and fish tank.
The second link in particular details how to do water changes, the equipment required, and the importance of having no chemical traces (such as the example you give about washing-up liquid) - the sink itself would not be needed, just the water from the tap plus the fishkeeping bucket. That and some of the other links also refer to how to clean items from the tank and that nothing else is required besides water.