Curiousbranching
Active Member
thank you, i'm a bit worried about the flow issue as it seems these balls are quite small, about 1-1.5cm.
Poor Man's Nutrients Control - Donovan's Nitrate Destroyer
- Thread starter Donovan Joannes
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blazn
Active Member
Recent posts in this thread have discussed concerns with potential clogging, reduction of flow in their DND. I ran into that myself recently, after almost 2 years of use. So, you have valid concerns in that smaller media certainly can cause your DND to clog with bacteria growth over time. Donovan, the creator of the DND and this thread, promoted using different sizes of media to 'encourage' better flow. The media in my DND is mostly comprised of 2cm spheres, so I'd recommend not going smaller than that, or mix in some larger media with it, in order to reduce clogging issues down the line.
Curiousbranching
Active Member
How did you deal with the clogging issue? Was it due to microbial growth or debris build up in the DND? I plan to draw water from the over flow tube so I am a little worried that there will be nothing to filter the debris before it enters the DND. I will receive the filter media tomorrow and will put the DND into operation, I have changed to a 1 inch bio ball after receiving your helpful advice, thanks again.
blazn
Active Member
I removed my DND from my sump, separated the PVC tubes and flushed each tube several times with fresh RODI. My DND resides in my sump where it really does not get any debris, the clogging was completely due to bacteria growth, which was visible, especially in the input tube. As my DND has been in operation for over 18 months, I may just have to flush it annually to reduce any bacteria build-up. I would be concerned if your DND input is from your overflow, as any detritus that enters will certainly add to potential clogging issues.
Curiousbranching
Active Member
That's a concern since I don't use filter socks. Maybe I should look into putting a mechanical filter on the DND inlet.
Curiousbranching
Active Member
So, my DND has officially been running for 48 hours! I used Mr. Donovan’s original prototype and tweaked it a little to match my actual tank volume, but I kept the ratios the same. I filled both towers with 1-inch bio balls, plus a few large ceramic rings—just big enough to block any bio balls from sneaking into the connecting pipe between the two towers.
On top of the first tower, I slapped on a coarse filter pad to catch any gunk in the incoming water. From what I understand, the first tower is mostly aerobic, so leaving it open should be totally fine. I’m hoping that pad makes the DND easier to maintain and less prone to clogging (because who has time for that kind of drama?).
Also, quick tip: when you first fire up the DND, crank the flow to the max for a few hours to purge all the microbubbles. Trust me—there’s no way you’re hitting that sweet, steady 5–10ml/5s flow rate without doing this first.
Right now, my NO3 is sitting at a chunky 30ppm. My goal is to bring it down and keep it stable at around 5ppm, all thanks to the mighty DND. I feed my fish like they’re living in a buffet, so managing nitrate the usual way is a losing battle.
Let’s see how this little beast performs when we hit week two! Stay tuned.
On top of the first tower, I slapped on a coarse filter pad to catch any gunk in the incoming water. From what I understand, the first tower is mostly aerobic, so leaving it open should be totally fine. I’m hoping that pad makes the DND easier to maintain and less prone to clogging (because who has time for that kind of drama?).
Also, quick tip: when you first fire up the DND, crank the flow to the max for a few hours to purge all the microbubbles. Trust me—there’s no way you’re hitting that sweet, steady 5–10ml/5s flow rate without doing this first.
Right now, my NO3 is sitting at a chunky 30ppm. My goal is to bring it down and keep it stable at around 5ppm, all thanks to the mighty DND. I feed my fish like they’re living in a buffet, so managing nitrate the usual way is a losing battle.
Let’s see how this little beast performs when we hit week two! Stay tuned.
blazn
Active Member
Looks good and sounds like you are on the right track! I also believe in heavy in and heavy out for nutrients, which makes the DND an essential tool! Be patient with it and it will 'clean up' after each 'buffet' and make your life easier and your tanks inhabitants much happier & healthier!So, my DND has officially been running for 48 hours! I used Mr. Donovan’s original prototype and tweaked it a little to match my actual tank volume, but I kept the ratios the same. I filled both towers with 1-inch bio balls, plus a few large ceramic rings—just big enough to block any bio balls from sneaking into the connecting pipe between the two towers.
On top of the first tower, I slapped on a coarse filter pad to catch any gunk in the incoming water. From what I understand, the first tower is mostly aerobic, so leaving it open should be totally fine. I’m hoping that pad makes the DND easier to maintain and less prone to clogging (because who has time for that kind of drama?).
Also, quick tip: when you first fire up the DND, crank the flow to the max for a few hours to purge all the microbubbles. Trust me—there’s no way you’re hitting that sweet, steady 5–10ml/5s flow rate without doing this first.
Right now, my NO3 is sitting at a chunky 30ppm. My goal is to bring it down and keep it stable at around 5ppm, all thanks to the mighty DND. I feed my fish like they’re living in a buffet, so managing nitrate the usual way is a losing battle.
Let’s see how this little beast performs when we hit week two! Stay tuned.
Gtinnel
10K Club member
That’s how I made mine too. I 3d printed a base with channels in it for the water flow and a cap for each pipe.
Yodaman
Active Member
I’m putting together a narrower setup so I built the bottom to have water pass through it, and the top to hold them together to help stabilize it.
I also have clear piping available at work I’m going to build it with, maybe I can provide some insight as to what’s going on inside the white pipe people are already using!
I also have clear piping available at work I’m going to build it with, maybe I can provide some insight as to what’s going on inside the white pipe people are already using!
blazn
Active Member
Now that would be cool to see! Being able to view bacteria growth would be an advantage, I think.
Gtinnel
10K Club member
I printed my caps as separate pieces but I did print thin rings that hold both pipes together.
I’d be interested if you could see the Nitrogen gas bubbling off the media and if so how much of the filter is anaerobic. The only downside I could see to the clear tube is the possible growth of algae but shouldn’t be an issue if you don’t have any strong lights near it.
Yodaman
Active Member
I have a Red Sea reefer 250, an old 1st gen, so it’s going in the back chamber next to the return pump, or next to where the drain pipes come down. Either way, in the back of the cabinet, and there’s no refugium in the sump, so it will stay dark (with the exception of some not very bright controller lights.)
I’ll report back with pictures once the reactor is complete as well as any photos during its use!
Curiousbranching
Active Member
So my DND has been running for almost 4 days now. I stopped dosing MB7 and started carbon dosing on day 3. So far, I haven’t seen any changes in NO3 levels coming out of the DND. But—I did start seeing this mysterious white slime forming at the output. That means I’m probably on the right track… right? I’ll report back on day 7 after checking the NO3 again. Stay tuned for the thrilling sequel!
Yodaman
Active Member
So I’m going to install a Tee in my return pump hose to feed the reactor. And I’m going to use a Dosing pump to feed carbon.
I got the tubes glued into the base and starting filling with ceramic rings (until I ran out.) I need to get another media to fill the remaining volumes. Then I will silicone the lid on
I got the tubes glued into the base and starting filling with ceramic rings (until I ran out.) I need to get another media to fill the remaining volumes. Then I will silicone the lid on
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MBruun
Active Member
You are for sure on the right track, with that white slime. That is from bacteria growth. If you measure NO3 on the outlet water, you should very soon see a reduction compared with the inlet water
MBruun
Active Member
Regarding the clogging issue, I experienced the same after around 18 month or so. I stopped dosing carbon for 3 days and then started the dosing again slowly ramping up. That solved the issue.
Gtinnel
10K Club member
What diameter pipe are you using? It may just appear this way in the picture but it doesn’t look like you have a lot of volume in the chambers.
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