Biologicals

Hello! We recently purchased a salt water tank and this is our first aquarium. We hired a company to come in and do the maintenance and add the live rock, coral, and so far four fish. They told me today that there the tank is not designed to have biologicals and they needed to add bio balls. Can someone help me with this?

Nowadays the salt water tank don't use bilogical unit, because it's dangerous.

To tell a long story short... with biological unit you'll have ever nitrate problem!

But using skimmer you'll have a far lower problem.

Don't use a bio balls