OK. So, if you bought it as an existing setup I assume that it is an established system and that the tank cycle has been completed.It was an existing tank, not too sure of the make but it is one that you can buy as a complete set up. It is small probaly only about 55 liters.
No need to worry, we were all new at one time, R/O water is water that has passed through a reverse osmosis filter, basically it is pure water, with all the minerals and toxins (not toxic to us but will build up in a tank...)It is a Boyu Nano Marine Tank - 58L, it has been established and was running for about a year. Basicly all I am looking for is a guide for maintaining the tank, will a test kit for tropical tank be good enough when testing the water in a marine tank?
With top up what is RO water, sorry to sound a bit doof here..