Nitrate Levels in Fish-Only Marine Tank

[post2338]

I currently have a 46g Freshwater community tank with 19 fish consisting of a mix of Live-bearers, Tetras and Gouramis. With weekly 25-30% water changes and monthly cleaning of the two cannister filters, my Nitrates never exceed 5ppm. From what I have been reading, if I took my same equipment and water change/filter cleaning processes and converted to a fish-only marine set-up with let's say 4 marine fish, that I would start to encounter excess Nitrate problems. Is this true? If so, why is this?

Thanks!

 

[OrionGirl]

Depends on the fish and the feeding--but it could. There's really not a comparison between maintenance in a reef and in a freshwater setup. Mechanical filters tend to trap solid wastes and contribute to nitrates in any system, but that doesn't mean it will always happen. I've kept UGF tanks with minimal nitrates, while others report not being able to keep nitrates under control with UGF. So much depends on how you maintain the setup. IME, if you can keep the nitrates low in FW, the same routine will keep them controlled in SW just as well--as long as the ammonia production is similar for both systems. A smaller bio-mass would be needed--marine fish respire ammonia at higher rates than FW fish, due to the need to process salts out of the water.