ULNS - Denitrators
 

What's the best option for keeping Nitrates near 0?

I have been cruising the web for ways to limit nitrates in my setup. I like the idea of ULNS, but don't like the idea of Zeovit for two reasons (I could be very wrong, so please correct me): by targeting the ammonia/ammonium, the tank is effectively not cycled, meaning there is no easy way off the system without a cycle/crash; dosing unknowns without testing and watching for changes to corals is not measurable enough to give me any sense of comfort.

As I understand it, this leaves few options if I want to keep nitrates near 0.2ppm: huge daily water changes; deep sand bed; bio pellets, carbon/coil denitrator, or a sulfur denitrator.

I have tried to find out why sulfur denitrators went out of style, or never caught on in the first place. If anyone can help me figure this out, I would appreciate it. I can't find too many down sides to them, aside from having to monitor pH, dose Alk, and keeping an eye on ORP values on the aquarium and effluent as a method of monitoring the viability of the bacteria within.

I can anticipate similar potential issues with the bio pellets (unstable and aerobic makes potential crashes more likely) and the carbon/coil denitrators (require specific dosing of a carbon source), but still don't understand why they haven't caught on as well?

If anyone can shed some light on this, I would greatly appreciate it.

I don't know much of denitrators however, I am a firm believer in large wc and vacuuming the sand bed. You may want to target .1 or .2 nitrate level instead of 0 and I also recommend keeping your phosphate levels in check as well.

Thanks for the post... I think there are a lot of people in the same boat, not knowing about denitrators. I suspect that's for a good reason that I just can't figure out yet. I agree with the water changes and vacuuming.

FYI:

Targeting 0.1-0.2ppm, currently running GFO to keep phosphates <0.03ppm, and ideally lower.

I also plan on doing a 15% WC weekly, which I hope to turn into a 15% continuous water change... but that's for a different thread.

Also, I am just wrapping up the cycle, so my bio-load is nil. I just was researching ZEOvit and because they recommend starting it on a new system, and I like some aspects but not all, so I hoped to compromise with a denitrator.

I can't find too many downsides on the web, but they are rather unpopular, so that must be for a reason.

The best method for keeping nitrates near 0 is a well set up tank with sufficient good quality live rock to support the bio-load. This is also the most bulletproof. Keep it simple!

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Agree! wc is to reduce and maintain along with good skimming.

How does the size of my filtration system control Nitrates? Aren't nitrates the end of the nitrogen cycle? I understand how LR can control nitrites, by converting them to nitrates, but from there I am lost.

Nitrates are consumed by the anaerobic bacteria in the low oxygen area inside the rock.

Really? That's a great suggestion. It must operate similar to a deep sand bed. I bet you need a ton of live rock and very little flow to make that happen. It sounds like its not something for a display... I think I have seen that setup at Wai's in Calgary. He has a SH Ton of LR in a ~300Gallon with very little flow.

Has anyone had success maintaining 0.1ppm Nitrates with 10-15% water changes weekly with a setup like this?

I doubt I have enough space to setup another aquarium for LR for my 700gallon total volume system. Unless this doesn't take as much real estate as I am thinking.

Thanks again for the info.

I don't believe that there is such a thing. :-). There are lots of options, all of which you seem to be aware of already.

Maybe set up a poll to see which of the ones you listed seem to be the most trendy these days.

b09u5,
Both coil and sulphur denitrators went out of style because they were prone to clogging or when vunerable to power failures, gave you an H2S problem.
Maintaining a slow constant flow was critical with them.
Follow the suggestions everyone else here has listed and you should be fine.