Poor Man's Nutrients Control - Donovan's Nitrate Destroyer

[legionofdoon]

I have around the same water volume as you. I used 3 inch pipe without issues. My numbers should be on one of my previous posts. Spend the money and get a PVC needle valve to regulate flow off the supply pump do not restrict the output. It takes about 1-2 months to start working. I'm keeping my nitrates around 10 right now but you can go lower with this if you want. The flow rate recommended is for the start up. You may need to increase the flow in the future to prevent Hydrogen sulfide from forming in the reactor. Once the bacteria use up the nitrates in the reactor they switch to sulfur. If you increase the flow it'll supply more nitrates into the reactor. Any time I smell sulfur I slowly increase the flow til I don't. You will get slime on the output at first but once your nitrates decrease it'll clear up as the bacteria have less food to multiply.

 

[legionofdoon]

Page 65 is my build.

 

[mattie_07]

I have around the same water volume as you. I used 3 inch pipe without issues. My numbers should be on one of my previous posts. Spend the money and get a PVC needle valve to regulate flow off the supply pump do not restrict the output. It takes about 1-2 months to start working. I'm keeping my nitrates around 10 right now but you can go lower with this if you want. The flow rate recommended is for the start up. You may need to increase the flow in the future to prevent Hydrogen sulfide from forming in the reactor. Once the bacteria use up the nitrates in the reactor they switch to sulfur. If you increase the flow it'll supply more nitrates into the reactor. Any time I smell sulfur I slowly increase the flow til I don't. You will get slime on the output at first but once your nitrates decrease it'll clear up as the bacteria have less food to multiply.

As I have limited height in the all-in-one chambers, I have about 12" in width, so I chose the largest diameter I could fit. I've ordered 2 boxes of Maxspect Nano-Tech Bio-Sphere (in total 160 spheres) ,1 box of large bio rings, 1 box of small bio rings and 1 box of ceramic rings. I will try to use as much as possible of the spheres since these have the biggest surface area for the bacteria. I will fill the empty space with a combination of the large & small bio rings. I'm making the U shape version, so at the bottom (joining the 2 towers) I will place the ceramic rings.
For the bacteria I've ordered Seachem Stability (spore form, so can withstand temperature swings during transport and contain aerobic, anaerobic, and facultative bacteria).

 

[legionofdoon]

It will seed on its own over time.

 

[olonmv]

My ICP results. Last water change was in September '22. I dosed all for reef , amino acids from brightwell and, manganese from stock solution I made. I stopped dosing AFR about a month prior to sending samples. although my water chemistry seems good I'm having issues with polyp bailout, so gotta figure that out. the denitrifier works as advertised.

 

[Gtinnel]

So I’ve been contemplating making one for a long time and after reading this entire thread, I’ve finally decided to make a Donovan’s nitrate destroyer. Instead of using store bought pvc fittings I am 3d printing the bottom and top cap for the cylinders with holes for the inlets and outlet

I am planing on using 1/4 rodi tubing for the inlet and output. I assume 1/4 hose for the inlet is fine, but is using that small of a line a bad idea for the output. I know going to big will allow air to flow back in from the output, but I’m not sure if 1/4 is too small and will clog too easily.

 

[Joj]

Huge thank you to Mr Donovan for his contribution to our hobby - continue to RIP sir.

I created mines after stumbling onto this thread after I’ve upgraded to my 500g (6’x4’x3’) FOWLR 2 months ago. With a huge fish load and heavy feedings, I’ve climbed to about 80 nitrates And holding steady there. Fishes are acting fine besides my Queen angel with slight pitting in her face (possible start of HLLE?). So I wanted to keep nitrates down since I can’t do massive water changes (no room for 200 gallons water tanks).

So about 2 weeks ago, I put in-line the DND and started dosing MB7 for a week along with 5mL vodka daily . Took about 2 weeks to see the effluent nitrate level drop to 0. Hope my 80 nitrates will drop over the next two weeks too since it’ll be like daily 10% water changes going forward.

quick stats:
-10’ 3” tubing cut in half with 90 degree elbows
-about 65 inches tall
-about actual 3.5 gallon water capacity in DND
-running MJ1200 to feed it with 1/4” tubing and John Guest shutoff valve for inlet control
-outlet is 1/“4 RO tubing but able to disconnect it and run 5/8” for clearing clogs if needed.
-running about ~20g per day right now thru it. Will try to increase flow to 45g per day (20mL per 10 sec thru it as my goal (10% daily water volume).
-dosing currently 5mL vodka daily thru BRS doser
-end goal is to not have to dose vodka (or very little) but let the DND do it’s thing with anaerobic Bacteria and keep Nitrates realistically around ~20
-3” 10’ piping and elbows ~$70
-ceramics filter rings and bio balls +vodka and MB7 (got the biggest ones possible .75-1” to prevent clogging) materials off Amazon ~$110
-DND total cost - close to ~$180 (had RO tubing already along with old MJ powerhead, pvc glue). Should save in long run with less salt for water changes.

 

[jtroxel1]

My current setup in a 10G sump. The twin white thinggy is the reactor.

I'm just learning about this after Sanjay Joshi presented at Aquashella here in Dallas (2023); during his discussion he identified your DND as a good solution to lower nitrates. I'm excited to build my own, but I do have a couple of questions:
1. What is the container with the black lid on top of the right cylinder? It looks like the top of a protein skimmer, but your diagram doesn't show this.
2. Your inlet (whether pump assisted or off the return) makes a lot of sense, but where does the outlet go? Does it just drip into the sump filter sock - aka, your coffee filter that you mentioned in your success story for week two that you mentioned you had to squeeze out? I'm confused becausein the picture that you posted in June of '17 showing one of your members capturing the bubble in the tube (I'm assuming this is the outflow tube), this tube looks pristine and clear without anything I'd want / need to send to a filter sock.
3. As I'm laying out my build plan, I started wondering: is the distance between the two cylinders critical? Yours are side by side, but if I wanted to put a few or many inches between them with a longer nipple/pipe, would this affect the effectiveness of the system?
4. Along the same lines, is there a reason that these two pipes can't share a common bottom container - i.e., a shoebox shaped container that would hold both tubes up? So instead of being connected only by a 1" diameter nipple, both tubes would be threaded into an approximate 2 - 3" height, 5 inch deep, by 12" wide watertight base, perhaps with another layer of media. If you're familiar with Bashsea, they have bases like this on a lot of their reactors (Image for reference: https://tinyurl.com/ysa48mcp)
5. You mention measuring the effluent and the nitrogen gas bubbles:
a. Nitrate: are you referring to a standard nitrate test kit (e.g. Hanna electronic or Salifert manual testers) and are you testing just the effluent, or the tank water?
b. should we be off-gassing the nitrogen bubbles from the return line so that it doesn't go back into the sump?
i. assuming your answer to #2 is that it exits the reactor and drips into the sump sock (instead of being piped under the water line, then I assume the nitrogen bubbles take care of themselves; is that correct?

Thank you for posting about this, and for any help in resolving some of these questions.
Jason

 

[Feiwen]

Man what a read. RIP Donovan. So just to make sure i'm understanding this correctly. Once I hit my targeted Nitrates in my tank (10), the effluent should match that correct. So as long as I'm above my target nutrient level the effluent should be at 0 nitrates?

@olonmv

 

[oliverout]

Wow!!!

 

[blazn]

RIP Donovan...I am very thankful in how you shared your insights with the reefing community!

After reading this entire thread, basically twice, I joined the DND club and I'm so glad that I did! Over the last 2 years, I had increased the fish load in my 120g DT and due to my belief in robust feeding, my nitrate levels had unknowingly increased to 70+. As I had/have zero algae issues, the nitrate increase had occurred without me realizing it, but over time I had noticed a negative impact on my corals and an ICP test alerted me to NO3/PO4 issues.

Since then, I started using a restrained amount of GFO in a reactor, which has controlled the PO4. I created a DND using a pair of 27" long 4" PVC pipes, filled with Aquaneat brand media balls & rings (mentioned in prior posts on this thread), totaling approximately 3 gallons in volume. I started daily dosing MB7 on 7/4 (initially 5ml/day, increasing to 10ml/day, continuing until the bottle was empty) and a couple days later started dosing 5ml vodka per day, split into 2 doses. After a couple weeks, I doubled the vodka to 10ml/day and the nitrate level slowly started to reduce. After a couple more weeks, I increased the vodka dose to 18-20ml/day and at that point did have some visible bacteria film on the DT glass for a few days, but I never experienced any clogging issues. After a month since putting my DND into production, my NO3 was down to 45. One week later it was 26. One week later (2 days ago, 48 days after starting) it was down to 13. I'm now reducing vodka back to 10ml/day and will continue to reduce until I reach the proper maintenance level. If you're struggling with high nitrates, I HIGHLY RECOMMEND building yourself a DND and put yourself back in control of your NO3. A DND will be an essential tool in my reefing toolbelt from now on! THANK YOU DONOVAN and all who contributed to this valuable thread!!

 

[piranhaman00]

Started reading through this, can anyone help with some questions?

I have 400 gallon system.

What height for the 2 4” towers?
What should the flow rate be out of the output?
Is the carbon really does into the top of the first tower? What volume should be dosed to start?
What media are people using to fill the towers?

Thanks,

 

[blazn]

Started reading through this, can anyone help with some questions?

I have 400 gallon system.

What height for the 2 4” towers?
What should the flow rate be out of the output?
Is the carbon really does into the top of the first tower? What volume should be dosed to start?
What media are people using to fill the towers?

Thanks,

Height of the towers would be mostly defined by the space you have for them. The bigger the reactor you build, the more productive it will be. The flow rate should be slow, but continuous. Donovan indicates to aim for about a 10% daily turnover rate. Yes, the carbon source is to be added a the top of the 1st tower. I followed Donovan's recommendation by starting dosing bacteria (MB7) daily, followed by starting carbon dosing a couple days later. Using vodka, I started with 5ml/day (split between 2 doses) and ended up increasing up to 20ml/day until I reached my NO3 target, at which point I reduced vodka to 12ml/day, which is maintaining my NO3 level. Media just needs to contain a lot of surface area for bacteria growth & be bulky enough not to clog. I used Aquaneat brand media balls & rings.

 

[piranhaman00]

Height of the towers would be mostly defined by the space you have for them. The bigger the reactor you build, the more productive it will be. The flow rate should be slow, but continuous. Donovan indicates to aim for about a 10% daily turnover rate. Yes, the carbon source is to be added a the top of the 1st tower. I followed Donovan's recommendation by starting dosing bacteria (MB7) daily, followed by starting carbon dosing a couple days later. Using vodka, I started with 5ml/day (split between 2 doses) and ended up increasing up to 20ml/day until I reached my NO3 target, at which point I reduced vodka to 12ml/day, which is maintaining my NO3 level. Media just needs to contain a lot of surface area for bacteria growth & be bulky enough not to clog. I used Aquaneat brand media balls & rings.

So you used all the same media? Not all different types like his first image shows?

I will be dosing vinegar. What is the recommended started dosage based off of?

 

[blazn]

So you used all the same media? Not all different types like his first image shows?

I will be dosing vinegar. What is the recommended started dosage based off of?

I only used 2 types of media: Aquaneat bio balls & Aquaneat ceramic rings. You certainly can go with a single type of media, as the entire purpose is just to contain plenty of surface material for housing bacteria without clogging. I used the bio balls for the majority of my reactor but used the ceramic rings around the base of each tower, where they connect, to reduce the chances of clogging at the connection. I have yet to experience any clogging.

I have no experience dosing vinegar, but everything I've read indicates that vinegar is dosed at 8x the rate of vodka.

 

[piranhaman00]

I only used 2 types of media: Aquaneat bio balls & Aquaneat ceramic rings. You certainly can go with a single type of media, as the entire purpose is just to contain plenty of surface material for housing bacteria without clogging. I used the bio balls for the majority of my reactor but used the ceramic rings around the base of each tower, where they connect, to reduce the chances of clogging at the connection. I have yet to experience any clogging.

I have no experience dosing vinegar, but everything I've read indicates that vinegar is dosed at 8x the rate of vodka.

Are these the bio balls you used? I see the plastic ones but I feel like those are outdated now. I am also thinking about using seachem matrix.

 

[blazn]

Are these the bio balls you used? I see the plastic ones but I feel like those are outdated now. I am also thinking about using seachem matrix.

Yes, that is the bio balls I used. You definitely do NOT want to use plastic ones.

 

[Gtinnel]

Are these the bio balls you used? I see the plastic ones but I feel like those are outdated now. I am also thinking about using seachem matrix.

I build a nitrate destroyer a few months back and that is the same media I used. I’ve been having issues with my outlet plugging but so far the media hasn’t had any issues with plugging up and restricting flow.

 

[piranhaman00]

Yes, that is the bio balls I used. You definitely do NOT want to use plastic ones.

I build a nitrate destroyer a few months back and that is the same media I used. I’ve been having issues with my outlet plugging but so far the media hasn’t had any issues with plugging up and restricting flow.

Have you both had good results?

I plan to use 4” pvc, can you estimate how high the 1 gallon bag of those balls filled the pvc? Im wondering how many I will need. Thanks!

 

[Gtinnel]

I plan to use 4” pvc, can you estimate how high the 1 gallon bag of those balls filled the pvc?

4” pvc should have an internal dimension of 4 inches so to find the area of a cross section is pi times r squared. So 3.14x2^2 which is 12.56 square inches. A gal is 231 cubic inches so 231/12.56 means that each gallon would fill roughly 18.4 inches of a 4 inch pipe.

I’ve not had the best luck with mine but the outlet has plugged many times and I’ve been too lazy to unplug it within a reasonable amount of time. I also emptied my diy NoPox dosing container and haven’t filled it. So my experience probably isn’t fair.