Reducing Nitrates - Canister

[Ossy3]

Hey Guys,

I run a reef tank with two canister filters. Unfortunately my nitrates and phosphates are quite high, I do water changes every week but this doesn’t seem to have much of an effect. I know the long term solution is to move to a tank with a sump. However, are there any tips in the meanwhile I can utilise to try bring down the nitrates and phosphates. Tank is 4ft long and has about 290 litres.

 

[DaddyFish]

What brand/type of canister filters?

 

[Ossy3]

What brand/type of canister filters?

Aquaone Canister filter, one is a 700 & other is a 1200. The 1200 is also connected to a UV-Sterilizer.

Thanks

 

[DaddyFish]

Anaerobic bacteria might be your best bet. You could add another piece of (external) equipment like an algae scrubber and it would do an excellent job of consuming nitrates and phosphates.

I just studied the Aqua One 700 from a YouTube video.

You could take out all the foam/floss etc. and fill each section with Seachem Matrix. Reduce the flow rate to a minimum and have it intake from the bottom only. The idea is to have a super-slow flow over the Matrix biomedia. That will act somewhat like a deep sand bed once the anaerobic bacteria colonize the inner portions of the Matrix. Be prepared to be patient. It will take at least 4-6 months for bacteria to colonize the inner depths of the Matrix. You'll know it's working when nitrates level out and cease to climb.

My recommendations in summary...
1. Switch to a canister filter that has an easily removeable prefilter section (Oase Biomaster) so that organics can be removed by mechanical filtration that gets cleaned every week BEFORE they have a chance to decompose into the water column.

2. Add an algae scrubber as external equipment to consume nitrate/phosphate.

3. Convert your existing canisters to a dual setup. One high flow doing mechanical and bio for Ammonia-Nitrite-Nitrate. The other very slow flow (< 50 gph) over Matrix to host anaerobic bacteria for nitrate reduction.

 

[Ossy3]

Anaerobic bacteria might be your best bet. You could add another piece of (external) equipment like an algae scrubber and it would do an excellent job of consuming nitrates and phosphates.

I just studied the Aqua One 700 from a YouTube video.

You could take out all the foam/floss etc. and fill each section with Seachem Matrix. Reduce the flow rate to a minimum and have it intake from the bottom only. The idea is to have a super-slow flow over the Matrix biomedia. That will act somewhat like a deep sand bed once the anaerobic bacteria colonize the inner portions of the Matrix. Be prepared to be patient. It will take at least 4-6 months for bacteria to colonize the inner depths of the Matrix. You'll know it's working when nitrates level out and cease to climb.

My recommendations in summary...
1. Switch to a canister filter that has an easily removeable prefilter section (Oase Biomaster) so that organics can be removed by mechanical filtration that gets cleaned every week BEFORE they have a chance to decompose into the water column.

2. Add an algae scrubber as external equipment to consume nitrate/phosphate.

3. Convert your existing canisters to a dual setup. One high flow doing mechanical and bio for Ammonia-Nitrite-Nitrate. The other very slow flow (< 50 gph) over Matrix to host anaerobic bacteria for nitrate reduction.

Hey mate, thanks heaps for the advice. Will get onto it straight away. When you mention algae scrubber, I've got one of the flipper models I use, pretty good for what it does I guess.

 

[DaddyFish]

I forgot to mention... You could buy a bunch more corals to consume the extra nitrates.
;Woot

 

[Ossy3]

I forgot to mention... You could buy a bunch more corals to consume the extra nitrates.
;Woot

Now we're talking haha, what corals would you recommend?

 

[DaddyFish]

Now we're talking haha, what corals would you recommend?

Softies and LPS are nitrate munchers.

 

[Ossy3]

Softies and LPS are nitrate munchers.

Just one more question, do you think by running two cannisters (with similar set-ups), that this could've actually increased the nitrates in my tank. Just opened my Aqua 700, although it did stop alot of the gunk and that, I feel like running two cannisters may have increased the nitrate back into the tank..

 

[DaddyFish]

Just one more question, do you think by running two cannisters (with similar set-ups), that this could've actually increased the nitrates in my tank. Just opened my Aqua 700, although it did stop alot of the gunk and that, I feel like running two cannisters may have increased the nitrate back into the tank..

If your question is... "Did running two canisters instead of just one increase(double) the nitrate production in my tank?"

The answer is no, it did not. The buildup of nitrates in the water column is a direct result of how much you feed. You feed according to the livestock's needs, so more livestock means more food required and more ammonia-nitrite-nitrates produced out the back end of the cycle.

Canisters are great filtration right down to the production of nitrate. They typically have high flow, good mechanical filtration and will readily attack ammonia. Contrary to the impression one might get from so much online comment about canisters being "nitrate factories", they don't magically manufacture extra nitrates. They mechanically filter the organics and debris and process Ammonia-to-Nitrite-to-Nitrate. However, if the mechanical media isn't cleaned at least once per week, the trapped particles rapidly decompose into nitrates that are then returned to the water column.

The trick is breaking down and getting rid of the nitrates as nitrogen bubbles, food for plants(algae), food for bacteria(carbon dosing) etc. There are many ways of attacking nutrient export (nitrates, phosphate), canisters typically do not provide the very slow flow, low oxygen environment to support anaerobic bacteria that break down nitrates. In my opinion an algae scrubber is probably the best addition to a canister system added for processing excess nutrients.

 

[brandon429]

your tank does not need the canisters at all, you can run them empty. your nitrate will stay the same, but it will help to show design options that reef tank never, ever need extra surface area beyond the display, it doesnt help stabilize anything.


fish kills and disease losses that cause tank crashes still happen when the extra surface area is present, it literally doesnt help anything its merely something we've carried over from the freshwater hobby. if you run both canisters empty and use them only for filtration, nothing bad happens to the reef. you are not tied to them whatsoever, merely the current they provide is handy. you could remove both of them instantly, hook up powerheads, and it would be an easier system to manage w fewer leak points etc.

the media is so unimpactful that you can remove them instantly, the system is not adapted or dependent on the media whatsoever, even if your up front display is bare bottom and rocks only, that's still the most surface area you'll need in any reef.

your nitrate if measured by another kit would just read some other number, none of this is in reaction to nitrate its merely a way to streamline how you reef, with more freedom. I guarantee you if polled, all owners of canisters feel their reefs are tied immovably to the surface area...not the case at all. we rip them offline all day long in our various works threads/tank move threads.

You are responding to a nitrate reading that any other kit would just wildly report differently, don't. its not worth being led around by params/inaccurate reads.

 

[blasterman]

This is easy.

Fill one of the cannisters half full of bio pellets. No need to make other adjustments.