Nitrate removal system

[reiters]

I was reading up on nitrate removal and thinking about the pros and cons of each method. I started thinking that maybe something could be built to remove nitrates and limit the cons. Please don't flame me if the idea is stupid or has already been discussed.

Build a black acrylic box that the top can be opened and closed. The box should be air/water tight when closed. Fill the box with layers of plastic canvas. Put hole near the bottom of one side for a water line that hooks to a dosing pump. The dosing pump should draw from the tank in a clean area through activated carbon to remove non-dissolved (no poo, food or critters) impurities. Put a one-way valve on the other side of the box as a out only as an exit for the cleaned water. Put a valve on top of the box for releasing nitrogen gas.

Again this may be a totally stupid idea. Rock converts nitrates to nitrogen once the water seeps deep inside which is rather slow. A deep sand bed can get saturated with bad stuff. The box wouldn't have a source for particles to collect as they are filtered out by the activated carbon. The plastic canvas would serve as surface area. The one-way valve would release the "cleaned" water as the pressure built and the top valve would be to release the nitrogen that was converted inside. The reason for black acrylic is to prevent algae from growing. The dosing pump would be used to feed tank water to the box on a timed basis.

So everyone please shoot holes in the idea in a friendly manner. If the idea sounds plausible then one can be built and discussions on ways to make it better.

The whole idea is to create an anaerobic area in a controlled manner.

 

[reiters]

One of my fears is that it would create hydrogen sulphide near where the dosing pump pushes in tank water (that has oxygen). I theorize that something will grow at that area to take up the oxygen as long as the dosing isn't too fast.

 

[Windy2]

Why not use a de-nitrator? They have been around for years and use a long tube to get an anaerobic area.

 

[reiters]

Honestly because I didn't know about them. I just did some checking to educate myself. It looks like a great solution for a nano but wouldn't be able to process enough for 230g (my setup). I can't say my idea would handle any more or even work but a few drops processed per second isn't going to make a significant change in a large tank. I might make one for my daughters 36g that doesn't have a sump but has a HOB skimmer.

 

[reiters]

So my issue with nitrates is that mine climbed to around 20-30ppm BUT my phosphates are unmeasurable low. Algae doesn't want to grow with no phosphates so they don't work as a means for removing nitrates. I haven't pinpointed the source of my nitrates at this point. I feed lightly. I have 5 fish and a lot of corals in 150g of water. I have 100lbs of good rock and 80lbs sugar fine sand in 135g tank. The 230g I mentioned earlier is the tank im am moving to in the next couple weeks. My sump has macro that in 6 months has doubled. Tank has been up for 1 year. I'm not in panic mode because while 20-30ppm isn't great, it's also not devastating. This thread isn't about me and my tank and more about a way to "naturally" remove nitrates. Something that could process even a cup of water a minute would probably do fine. I'm just trying to see if the idea floats.

 

[KafudaFish]

Go to the diy forum and on the first page should be a discussion on how to handle them in a large system.

 

[ReefWreak]

This sounds sort of like your originally stated idea, except with more eggcrate, and feeding it.

"DIY Natureef Style Denitrator Build and Data thread..."
With over a year and a half of data and experience in it.

Also, RE: Coil Denitrators, it sounds like they're scalable, but I believe they're almost always running at almost a drip rate by function of the way the reactor works.

The way you phrased it made it sound like you were alluding to that a slow drip rate couldn't possibly be useful in a large tank. A slow drip rate of copper will make a big difference, even a huge tank, but less absurdly, even a calcium reactor setup on a large tank (>200g) will still usually be a quick dribble of water when running full-tilt.

 

[reiters]

I do have my doubts that a small denitrator could effectively process a large tank. There is a big difference between dripping concentrated additives and removing impurities. The additives are being depleted by the growth rate of the corals which is a limiting factor. Nitrates are being added by several sources and can be increased significantly by overfeeding a few times and stay high until food biodegrades. I guess my thinking is a single piece of shrimp can cycle a large tank so how much nitrates does 10 fish produce in food and waste.

I don't rule out that i'm simply and completely wrong.

 

[Ron Reefman]

Until my Cheato got a good start and my DSB got established (both in 45g sections of my sump/refugium) I used a coil denitrator on my 400g system and it worked perfectly for a couple of years until I didn't need it any more.

 

[reiters]

Can you give me an idea of the size of the denitrafier and bio load? I have sand now but when I switch tanks I may go bare bottom. That doesn't mean I cant put a deep sand bed in the sump (75g).

 

[FloMotion]

Have you googled carbon dosing or vodka dosing? This is what I use to control nitrates and it works great (cost effective too).

 

[elegance coral]

FWIW
Back in the day,(late 80's/early 90's) I took a 10 gallon tank, filled it with bioballs, added a maxijet pump inside, siliconed an acrylic sheet on top, added an airline tube with a check valve (for gas to escape), and added a feed pump line and a discharge line. The feed pump was on a timer and ran a few minutes once a day. I fed the 10 gallon with vodka.

This was on a 55 gallon tank. While I was able to maintain very low NO3 levels with this system, it just became to much work. Constantly testing NO3 and adjusting the dosage of vodka wasn't fun, and this system didn't address the problem with PO4.

Now I simply design and maintain systems so that they don't manufacture a great deal of NO3, or PO4 in the first place. For me, this is much easier than trying to fight these fertilizers after they've been produced.

Peace
EC

 

[tmz]

As sulfur dentirator is another option to consider for higher volume needs.

Personally, vodka and vinegar dosing directly to the sump plus skimming has been my preference for the last 6 years or so for PO4 and NO3 control in a large heavily fed system.

Some clarification on other points:

Rock converts nitrates to nitrogen once the water seeps deep inside which is rather slow.

That's true but it's not the only place anaerobic dentrification occurs.Denitrifying bacteria remove the nitrogen either aerobically or anaerobically. They are facultatative using up the oxygen in an areas assimilating some nitrogen along the way and then when there is no more free oxygen they go after the oxygen in NO3. This whole process can occur within their own mats or in very shallow surface areas. So ,tanks without deep sand beds can works quite well in terms of dentirication.

The box wouldn't have a source for particles to collect as they are filtered out by the activated carbon.

GAC(granulated activated carbon) takes up dissolved primarily hydrophobic compounds; it's not much of a particulate filter.

The plastic canvas would serve as surface area.

That wouldn't provide much surface area vs something like bioballs.or some type of beads. I think it would be difficult to maintain much flow without boosting the bacteria with an organic carbon source.; with high flow it would be likely to serve for ammonia oxidizing bacteria which produce nitrate.

 

[reiters]

I've actually read quite a bit about carbon dosing. In fact I built a little app to help me out with the calculations and logs. Carbon dosing has one critical critetia that I currently can't meet. It assumes you are running a oversized skimmer. The current tank I have is on a stand that doesn't have enough room for the needed size skimmer. I have a Seaside Aquatics ES5 on a 135g with 40g sump. The stand height limits any other skimmer. I already own better skimmers but I can't get them in there. This is the number one reason I am changing tanks. I found a nice 180g 4'x4' tank and I'm building the stand.

http://www.keithreiter.com/dosing/

I think some of the methods assume you have PO4 and NO3 to operate. My tanks PO4 are too low for my tester and NO3 is at 20ish. I think that's why my macro doesn't grow.

After thinking about the discussion here, I wonder if an inline activated carbon cartridge being drip fed would work. No reason to build anything and it has HUGE surface area for bacteria growth. Not using it as a filter but using it because of the surface area.

Thanks to all for chiming in. It's great to hear what others think.

 

[FloMotion]

I've actually read quite a bit about carbon dosing. In fact I built a little app to help me out with the calculations and logs. Carbon dosing has one critical critetia that I currently can't meet. It assumes you are running a oversized skimmer. The current tank I have is on a stand that doesn't have enough room for the needed size skimmer. I have a Seaside Aquatics ES5 on a 135g with 40g sump. The stand height limits any other skimmer. I already own better skimmers but I can't get them in there. This is the number one reason I am changing tanks. I found a nice 180g 4'x4' tank and I'm building the stand.

http://www.keithreiter.com/dosing/

I think some of the methods assume you have PO4 and NO3 to operate. My tanks PO4 are too low for my tester and NO3 is at 20ish. I think that's why my macro doesn't grow.

After thinking about the discussion here, I wonder if an inline activated carbon cartridge being drip fed would work. No reason to build anything and it has HUGE surface area for bacteria growth. Not using it as a filter but using it because of the surface area.

Thanks to all for chiming in. It's great to hear what others think.

What is your skimmer rated for? I'm currently running an old euro reef skimmer rated for 75 gallons on a system with total water volume around 80 gallons. So I'm not sure that a "oversized" skimmer is necessarily needed for this method of nitrate reduction. As long as your skimmer is rated close to your total volume, you should be fine with carbon dosing. The key is to skim wet, so you may have to empty your collection cup more often than if you had an oversized skimmer. Just my .02