Increasing Nitrate with Trickle Filter?

[Fishbone]

Has anyone had success increasing nitrates without driving up phosphates by using a trickle filter with bioballs?

My tank is mostly softies and LPS, and I’m looking to bring nitrates up a bit while keeping phosphates stable (they’re already where I want them). When I try feeding heavier, phosphates climb quickly but nitrates only increase slightly.

I’ve also heard that protein skimmers remove more nitrate than phosphate, does anyone know if there’s any truth to that? If so, would dialing back the skimmer be a reasonable way to help bring nitrates up without impacting phosphates too much?

I know dosing is an option, but I’m wondering if a trickle filter or skimmer might be a simpler or more stable approach. Any firsthand experience or insight would be appreciated.

 

[Randy Holmes-Farley Verified Community Expert]

I don’t believe the skimmer even has a plausible rationale. It will have a small reduction in both N and P

I personally would not waste my time with a trickle filter, as I doubt the effect is large or easily controlled.
I think a far more successful and controllable way is to dose nitrate or ammonium.

 

[Fish Fan]

I remember trickle filters, and like Randy said above, I would skip them, or possibly save them for your aquatic turtle tanks, where I believe they are still used today.

Wet/dry-trickle filters were sometimes called "nitrate factories". If you could not keep them clean, which you can't practically do, they would often accumulate so much detritus that it would at some point just lead to very high nitrate. This isn't a big deal if you're keeping only fish or turtles, besides potentially fueling algae growth, but it's not great for reef tanks with corals.

And as Randy also said, this would not be a controllable way to increase your nitrate. The whole reason these filters fell out of fashion is because they would (seemingly) start to pump out nitrates without warning.

Long story short, listen to Randy Holmes-Farley

I hope that helps and good luck!

 

[Fishbone]

Thanks for the feedback. It sounds like dosing is the way to go. Is there any consensus on whether it’s better to dose ammonia versus nitrate from a coral uptake and coral health perspective?

 

[exnisstech]

I saw better results dosing ammonium than I did using sodium nitrate. I was having to dose nitrate daily to stay above zero. When I switched to ammonium bicarb I didn't have to dose as often to stay above zero. Could be imagination but I feel my SPS started growing a little faster. Eventually I was able to stop dosing and the tank stays 5-10ppm N but that could very well be the tank maturing and have nothing to do with switching to ammonium.

 

[Fish Fan]

Thanks for the feedback. It sounds like dosing is the way to go. Is there any consensus on whether it’s better to dose ammonia versus nitrate from a coral uptake and coral health perspective?

Generally speaking, it's easier (takes less energy) for coral to use ammonia directly vs. nitrate. Here's more from RHF on ammonia:
https://www.reef2reef.com/ams/ammonia-is-our-friend.1062/
And ammonia dosing for low nitrate:
https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/