High nitrates in a FOWLR system? (Hypothetical, for my own understanding)

[ReefSafeSolutions]

I just came across an article talking about how some FOWLR tanks are running with nitrates at 200-250ppm+ and that the fish are completely fine! I found this extremely bizarre so I did some searching online and it seems nitrates aren't as toxic to fish as ammonia and nitrite.

 

So, while I'm not running a FOWLR system, I am curious. I'd consider 10-20ppm+ to be high in a reef system, I always like to stay between 0-5ppm. But say I overfeed (which is certainly known to happen) and my nitrates go up to something like 30-40ppm. I know my corals aren't going to be happy, but according to my reading, the fish would be just fine.

 

Is that true? Do high nitrates not harm the fish?

[Tamberav]

Fish seem okay, however I would wonder if nitrates in the 200+ range long term would have negative effects over time not easily noticed such as shorter life spans. Sort of like how breathing pollution doesn't mean the effects are immediate or apparent but it's not healthy either.

 

Just a thought.

[mystersyster]

Hey man. Yeah that's pretty standard knowledge ;p

 

As far as how long they can tolerate high amounts of nitrate when they evolved in reefs that virtually have none... I don't know. I think it's important to keep fish as close to their natural environments as possible. It's only humane, especially if you are taking them out of the wild.

 

One other thing to look out for is algae growth with nitrate. This can hurt fish indirectly. This is a really good quick read you should check out.

 

http://www.wheatleyriver.ca/current-projects/wrig-pilot-nitrate-study/nitrates-and-their-effect-on-water-quality-a-quick-study/

[ReefSafeSolutions]

Great article. Basically, high nitrates can throw everything off balance and cause indirect stress and harm to the fish. That makes a lot of sense. High nitrates, high phosphates...algae factory.

 

The analogy of humans breathing polluted air is a good one. For some reason I was under the impression that high nitrates (I mean 30-40ppm, none of this 200+ garbage) caused more harm to the fish, but that's clearly not the case. Interesting.

 

Thanks for the input!