Effective Nitrates Removal

Hi,
I am looking for pointers to topics related to filter systems designed to effectively remove nitrates. I have heard about some large overflow (hob type) based filters where water runs slowly through heavily planted area where plants remove nitrates. But I do not know much about details and would like to learn.

My tap water used for water changes has zero NO3, so such filter would only be used as addition to typical closed loop bio filtration most tanks use.

The objective with using such filter would be to lower average nitrates level rather than reduce water changes which in my case are not a problem.

Thanks in advance for your help and pointers.

 

Hi! What test kit do you use? Some are very unreliable. I think you could use chemicals like aquadetox from API. Seachem prime could make the nitrates less harmful until your filter does the work or something as simple as a large water change could work like 50%.

 

Thank you, I do not have problem with high nitrates in my tank, which are around 10ppm.

What I am looking for is alternate ways of removing remaining nitrates other than adding chemicals, dripling systems or doing typical water changes which btw I do regularly.

For example, for almost two years I was using dripping system which kept my nitrates below 5 at all times, no problem. Trade of was however relatively high filter replacement cost and limitation in tank size where system was used.

Someone in separate topic on Fishlore described method based on using live potato being installed in the hob filter.
I am not saying it's something I would do, just want to learn some other solutions to improve no3 removal in closed cycle.

 

You're looking for a denitrification tower. Just keep in mind that water changes are still necessary. You can build your own, or buy a tower and set it up for what you want. There's a couple different ways to do it, but I've never looked too deeply into it. It's a curiosity for me so I never researched how to set one up. It does require a slow water movement through it to work, much like a weak uv light in a canister.

 

Plants. Plants. Plants. And more plants.
Fast growing, low light types are the best. Java moss, Java fern, crypts, vents, anything you have to trim back regularly cause every time you do you do you're literally and physically removing nitrates from your tank (or at least the result of nitrates being consumed by the plants as fertilizer).
If you really get them going you can make a deal with your LFS to trade them in for store credit too!

 

Thanks, yes I agree, plants are best nitrates removals.

Trouble is, despite my multiple successes in keeping and growing my fish including those presumed to be difficult like clown loacjest, discus, all growing like crazy in past two years forcing me to move to larger tanks...

the plants are in opposite. They simply do not grow in my tanks unlike fish.

Any new plant I get gets brown algae on it in time or develops dark green string like moss.

I suspect problem might lightning. But could it be also tap water which treated I use for rather frequent wc.

I have lights turned on for 12 hrs now, I can't say it's bright, rather moderate to low but everything of course is relative. I somehow can't imagine reducing light hours below 12 due to the family work schedule which members want to enjoy those few minutes in the morning before leaving to work or school. At evening the lights turn off at 7pm.

I could and forget about morning family "fish checking" shifting light on time to say 10am reducing light to 8 hrs a day. Trouble no one is home at 10 to feed fish in the morning. And for fish health I avoid feeding in the evening.

Then there is a tap water quality.
Fairly high ammonia level, zero nitrates and zero nitrites though. Moderate chlorine level of 2.5-2.0ppm (use Extech meter). All Prime treated before wc of course.
One thing is my tap to be super low hardness of KH=2 or 3 and DH of 5 to 6.

So the the plants are not growing at all and I simply replace these from time to time when they turn so ugly no one can watch them.

Fish in they meantime grow like nuts.

And yes, I have large biofilter bank of two Fluval 406's plus one Aquaclear 110 they keep my ammonia and no2 on zero no matter what I do which is good thing and keep my water column crystal clear at all times.

Could lack of plant growth be caused by low KH?

 

Plants do like a decent kh and gh, but unless you got a ph swing, there was likely enough kh. It's probably not enough lighting, not enough nutrients, and too long of a photo period. It's not easy growing plants in a discus tank due to the water levels discus prefer. You could probably do swords with root tabs and a 2 bottle all in one fertilizer though. Youd be dumping a lot of ferts down the drain with the frequent water changes though. Maybe a pps pro dosing regimen would be better.


Fyi, for a discus tank, pothos rooting or a denitrification tower will probably be better for you. Now I understand where you're coming from. At least until the discus are fully grown.

 

Plants do like a decent kh and gh, but unless you got a ph swing, there was likely enough kh. It's probably not enough lighting, not enough nutrients, and too long of a photo period. It's not easy growing plants in a discus tank due to the water levels discus prefer. You could probably do swords with root tabs and a 2 bottle all in one fertilizer though. Youd be dumping a lot of ferts down the drain with the frequent water changes though. Maybe a pps pro dosing regimen would be better.


Fyi, for a discus tank, pothos rooting or a denitrification tower will probably be better for you. Now I understand where you're coming from. At least until the discus are fully grown.

Thanks. FYI the pH is stable. Always 7.0-7.2.

I am recycling wc entire tank pretty much in a week period. I use overflow so do not take water manually out before putting new in unless doing vac every so often and in between wc is with new water mixes with tank water and pushes excess out through overflow.

Best results I had with smaller 65g tank having dripping system which was pushing 10gal over 24h period tap water filtered with dual carbon filter including one stage with coconut. Nitrates were below 5ppm at all times with trace of chlorine below 0.02 from filter pipe at all times with the flow speed I had (drop per second).

System had one flaw however because after a month super slow water flow was causing growth of some bacteria inside filter which was turning it into NO2 generator. Monthly replacements were expensive ($20 for coconut carbon filter insert only). And watching no2 levels coming out of filter was ridiculous (my tap has zero nitrites).

With my new 125gal tank I do not even think about adapting dripper due to expected cost and possible more maitnance of checking no2 levels and so.

I do standard wc using prime, results are good, fish happy but plants still do not grow.

What is pps pro?

 

Here are close ups of some plants... as much as I proud of my fish growing strong... plants are exactly the opposite







When I see those guys coming to me when I take those photos, I say, the **** with the plants but... it still makes me wonder what is going on?

 

Denitrifying bacteria! I had a similar issue with high nitrates in one of my tanks and someone pointed me in the direction of Seachem Matrix. Most of the "mainstream" media isn't designed to house denitrifying bacteria, only nitrifying, which is why our tanks end up with loads of nitrates. Seachem Matrix, Biohome ultimate and a few other medias are designed in a way where they have a not so porous centre where denitrifying bacteria can colonize in. After adding a few liters of matrix to my cannister filter I went from having a consistent 40ppm to 10ppm.

EDIT: Had denitrifying and nitrifying bacteria mixed up, lol.

 

It's trying to give the plants only what they need for 48 hours, instead of estimated index which aims to ensure there's no way to run out. Pps pro doesn't require a reset from wc if done correctly. EI relies on a 50 percent change weekly to "reset" the fert levels.

 

Those pictures show diatoms, and what looks like a beard algae or thick hair algae. That tells me your lighting period is too long. What if you took a 4 hour siesta when nobody is home via a timer? Is that an option? 12 hours is just begging for algae. The only time my tank sees that kind of lighting is when I'm actively trying to grow algae for the fish. You really need to be doing 4 on 4 off for lighting. That will give you an early time to view the fish and feed them, and a chance to see them after work/school.

 

Those pictures show diatoms, and what looks like a beard algae or thick hair algae. That tells me your lighting period is too long. What if you took a 4 hour siesta when nobody is home via a timer? Is that an option? 12 hours is just begging for algae. The only time my tank sees that kind of lighting is when I'm actively trying to grow algae for the fish. You really need to be doing 4 on 4 off for lighting. That will give you an early time to view the fish and feed them, and a chance to see them after work/school.

Brilliant, thank you. Yes my lights runs on timer now. I have just changed setting and adjusted it to 4-on 4-off 4-on plus remaining 12 hrs off during night time.

 

Brilliant, thank you. Yes my lights runs on timer now. I have just changed setting and adjusted it to 4-on 4-off 4-on plus remaining 12 hrs off during night time.

That should help a ton. Idk why you're getting diatoms unless your tank is under 6 months old. You should have silicates but the lighting fix should help all around. Keep in mind it's a gradual fix, and a good clean up crew will help keep it unnoticeable.

 

Try a sump like structure where the water is pumped. Load that thing with column feeders like duckweed, hornwort, anacharis, hygrophila, pogostemon, mosses, etc. Also, add some pothos roots into the “sump”.

 

Try a sump like structure where the water is pumped. Load that thing with column feeders like duckweed, hornwort, anacharis, hygrophila, pogostemon, mosses, etc. Also, add some pothos roots into the “sump”.

I agree, but a sump is a major diy task or additional expense. I think it's easy, but it's still pretty intimidating.

 

I agree, but a sump is a major diy task or additional expense. I think it's easy, but it's still pretty intimidating.

I love these type of challenges. As long as my wife sees the setup does not protrude walls to adjacent rooms in the house, I should be ok to try.

Check out my latest project...
Single Push Button Automatic Water Change Setup

 

I second the Seachem Matrix. Whether I change water every week or every two weeks, my nitrates consistently remain at 0. I used it in conjunction with Seachem’s bottled bacteria (can’t recall the name) for the first week of adding the matrix media. I did this to speed up the denitrifying bacteria colony since the bottle contains both aeroebic and aneroebic bacteria.

 

I second the Seachem Matrix. Whether I change water every week or every two weeks, my nitrates consistently remain at 0. I used it in conjunction with Seachem’s bottled bacteria (can’t recall the name) for the first week of adding the matrix media. I did this to speed up the denitrifying bacteria colony since the bottle contains both aeroebic and aneroebic bacteria.

One of my fluval 406 canisters is loaded with 1 liter of Matrix for sometime now. I inherited it from previous 65gal tank which was decommissioned with all biomedia and substrate transfered to new 125gal tank in just couple hours to to keep cycle. So that liter of Matrix is still alive and active.

But from what I read here this might not be even close to desired amount that would make difference for 125gal tank.

Shall I consider adding dedicated large canister filter with Matrix then? What would be recommended amount of it for the tank of this size? I appreciate any suggestions and recommendations.

 

Try a sump like structure where the water is pumped. Load that thing with column feeders like duckweed, hornwort, anacharis, hygrophila, pogostemon, mosses, etc. Also, add some pothos roots into the “sump”.

Sump with plants sounds like great idea. One thing I need to take care of before I invest in sump, is to make the plants grow in my system in the first place.

I have started from adjusting the lightning in my main tank and once I see the improvement I will take that lesson to sump design.

What's recommended light source for planted sump?

 

It depends on the tank size. If you are using a tank similar to a 20 long, I love the Beamswork light.

 

I got myself TDS meter today and it shows reading of 270 in main tank.

Btw, it measures also pH, and the result is way off vs. API test kit.

API test pH = 7.0
EXSTICK IK pH=7.99

Someone said API kit pH measurement has large error, so true.

Any comment on TDS having influence on my NO3?