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

[olonmv]

Many thanks for your quick reply. So you just used one media type: bio ceramic rings? You did not use Seachem Matrix? Would you be able to share which pipes you used: diameter + height, and how many media? This way I can estimate how much media I will need.

I will make 2 towers of 4" diameter and +- 23" in height.

Yes, I used just the one media and have been since September with success. I now have Matrix in hand but haven’t had to use it. The size of your denitrifier depends on your tank volume. What I did was take Donovan’s volume (80 gallons I believe) and divided it with mine and that gave me a multiplier. After you figure out what your DND volume is go online and search for a PVC volume calculator and you can play with various conduit sizes and lengths.

 

[mattie_07]

Yes, I used just the one media and have been since September with success. I now have Matrix in hand but haven’t had to use it. The size of your denitrifier depends on your tank volume. What I did was take Donovan’s volume (80 gallons I believe) and divided it with mine and that gave me a multiplier. After you figure out what your DND volume is go online and search for a PVC volume calculator and you can play with various conduit sizes and lengths.

Yes I already used your multiplier to design the towers All the PVC material has been ordered, and will be delivered tomorrow. I'm now searching for the media online and I'm guessing how much I will need... I will for sure buy the bio spheres (1,5" diameter, 80 pieces) and now looking how many bio rings, and ceramic rings I will need...

 

[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.