Biological Filtration in Reef tanks?

[cat325l]

Hi everyone, I am wanting to set up a nano tank and while I was researching different brands I ran across some information that I didn't quite understand. It was on the JBJ nano cube and it states:
Biological - Ceramic Rings & Bioballs provide the ideal environment for beneficial bacteria FISH ONLY tanks.
Why Fish Only Tanks? And what do you do with them if you plan on having corals and inverts? Thanks in advance for any info

 

[al mc]

Ceramic discs and bioballs provide excellent surface area for the colonization of the aerobic bacteria that complete 2/3 of the ammonia (nitrogen) cycle.
This part of the cycle removes ammonia and nitrites from the water which are toxic for fish. Fish tolerate nitrates well, unlike inverts like corals. So, for a fish only tank these biologic filtration accelerators are great.
You can use them in a reef, but will probably be making more frequent water changes than if you 'exported' the toxic for invert..nitrates..by using a refugium with macroalgae..like Chaeto. Plants like fertilizer..which is what nitrates are for them.

 

[cat325l]

That makes sense. The way I was reading it was like it would be harmful but it is just stating that i would need additional biological filtration to be adequate. Thanks for the info!