This is not my design. I read through a very lengthy thread on R2R by Donovan Joannes. He contributes quite a bit to the DIY reefing community.
I’ve struggled with Nitrates for a while. Due to all the normal reasons - over feeding, not proper ratio of cleanup crew, not frequent enough water changes, fighting protein skimmer etc.
Nitrates in my downstairs setup has pretty much hovered between 60 - 80 ppm for well over a year. I’m sure there were times it was higher. Perusing the internet and a few forums - I had seen plans and writeups for a DIY denitrator - I decided to build one and see if I could reproduce the results others were reporting.
I started with:
2 foot pieces of 4” PVC - 2
2 90 degree elbows
Various adapters and screw on cleanup fittings as can be seen in the photos.
A pump I had laying around
A gate valve
Some RO/DI tubing and random fittings to get the input line connected.
Media can be a little confusing - and easily the most expensive part of this. Various people use various things. Bottom line - you need something with a ton of surface area that won’t pack in so tight that it gets plugged up with bacteria slime.
I used 2 boxes of Ceramic rings - these are typically used in canister filters. https://www.amazon.com/gp/product/B000NRVLIU/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
A 8” X 8”X1” block of Marinepure ceramic biomedia - I bought 1 of these https://www.bulkreefsupply.com/marinepure-ceramic-biomedia-plate.html. This I broke up into random pieces.
1 1/2” Marinepure Ceramic Spheres - I bought 2 of these boxes https://www.bulkreefsupply.com/marinepure-ceramic-biomedia-1-1-2-spheres.html
I also pulled a couple small rocks out of my tank to help speed up the seeding of the new media.
Pictures work better than me trying to describe this - it’s pretty simple really. I have a cleanout one the top of the anaerobic chamber (output side) and a simple screw in fitting on the input side that allows me to dose a carbon source.
alt="fullsizeoutput_14b" />
I drilled a 3/16” hole, roughly 2 inches down, on the side of each chamber. I drilled one about 1/2” lower than the other side. The lower side is the output - so anaerobic chamber - and the higher one is the input. In my photos the input is the blue RO line - the output is just a hole. I had RO/DI tubing in the hole but it kept plugging up with the bacteria slime. Since this whole thing is sitting in my sump - I decided to just let the output run down the side. Eventually I’ll drill a larger output hole, screw in some sort of fitting and put an actual output tube - many to help prevent slime buildup on the side.
I’m running a small, random pump that I had sitting around the house. No idea what it is, how much flow. I have plumbed this with a gate valve and bypass output which allows me to turn the flow down to literally a drip if I want without creating much back pressure on the pump. I’ll show this in pictures and hopefully a quick video as I won’t be able to describe it properly here.
alt="fullsizeoutput_14e" />
alt="IMG_1305" />
alt="IMG_1303" />
So - what I have is a U shaped 4” PVC reactor (of sorts) with a small hole drilled in the side of each chamber, media filing the bottom half of the entire reactor. Pictures are easier than words for me so I’ll include them below.
alt="IMG_1302" />
alt="IMG_1301" />
alt="IMG_1303" />
alt="IMG_1309" />
alt="IMG_1313" />
You also need a carbon source. Use what you want - there are positives/negatives to any carbon source - honestly I don’t think it matters all that much - just pick what you want to use and use it. I use Red Sea NoPox - https://www.bulkreefsupply.com/red-sea-nitrate-phosphate-reducer.html . It works for me - again, use whatever you want.
I currently dose 6 ml per day - once a day - manually. Now that I know this setup will work I will implement a dosing pump for the NoPox and a smaller amount at least 2 or 3 times per day. This will also eliminate me missing days due to being forgetful.
I started running this around October 15. Took me a few days to get the flow dialed down to what was essentially a VERY slow but steady stream on the output side. I started dosing NoPox daily. I have NOT been religious about that though. We went on a cruise and were gone for 9 days and in all reality I probably dose 5 out of 7 days a week.
I knew things were starting to work due to the bacteria slime buildup in the output chamber. I’ve dosed carbon directly to the tank in the past and have experienced the bacteria bloom that is easy to get with that. I have NOT had a bacteria bloom in the tank or sump with this setup at all. Inside the output chamber is the only place I can see any of that slime. Photos below show the slimey goodness that many of us have seen throughout an entire tank when dosing carbon directly into the water column.
alt="IMG_1310" />
alt="IMG_1311" />
alt="IMG_1312" />
Roughly a month into this running I was able to measure my Nitrates down to 30 - 35 ppm Nitrates - they had been staying above 60 prior to this. Nothing else has changed. All good stuff, but not where I want my tanks to ultimately be.
About a week ago - holy cow, the STENCH - smelled like skimmate, kinda, but with a PUNCH. I’m talking - I walked into the house and could smell this stuff as soon as I opened the door. I knew it was coming from the tank area, I knew it smelled pretty much like skimmate, so I assumed it was my protein skimmer. I figured, hey, maybe it’s really pulling out a bunch of junk since I’ve got this denitrator working and I’ll just need to fashion up a skimmate locker with a carbon filter - THANKS to several members here for pointing me to that as a solution BTW. About a day later I decide “hey, I should look in the output side of that denitrator and see how much slime goo is in there”. MISTAKE, MISTAKE, MISTAKE!. I twisted off the cleanout plug from the anaerobic side and leaned over so I could look down into the chamber - I instantly understood EXACTLY where my new tank stench was coming from. HOLY COW - I can’t describe the smell that came out of there. I wish I could bottle it and send everyone some - it would be more effective than trying to describe it.
I knew I had read about the possibility of this - basically, if you don’t have enough nitrates in the anaerobic chamber the bacteria will find another food source and in doing so will produce hydrogen sulfide. I know it’s more complex than just that - but that is enough for us to understand that if your nitrates are too low you’ll eventually stink up your entire house. The good news is this is pretty easy to resolve. I simply increased the flow slightly and the stench went away within an hour.
This whole stanky house thing turned out to be a good thing. It prompted me to test my nitrate levels. I tested a sample that I pulled from the output of the denitrator and a sample of tank water. The results - were exactly what many others have experienced. While my tank levels are still fairly high - probably around 30 PPM or so - the levels coming out of the denitrator are well below 5 PPM. I always have to run my nitrate test diluted - on the high scale. Below, both samples are NOT diluted with RO. The sample on the left is 100% tank water pulled directly from my 60 gallon. The sample on the right is 100% water pulled directly from the output of the denitrator.
alt="IMG_1284" />
Bottom line - this thing is easy to build, can be done pretty cheap, easy to run - and it WORKS. I have some tuning to do for sure. Just like anything else in reefing there is going to be an art to tuning the dosing amount, schedule and flow through this thing to get nitrates at a nice low & steady amount.
Please feel free to ask any questions - I do NOT do a good job of writing things like this up, but I’m happy to offer up my experience with this so far.
I’ve struggled with Nitrates for a while. Due to all the normal reasons - over feeding, not proper ratio of cleanup crew, not frequent enough water changes, fighting protein skimmer etc.
Nitrates in my downstairs setup has pretty much hovered between 60 - 80 ppm for well over a year. I’m sure there were times it was higher. Perusing the internet and a few forums - I had seen plans and writeups for a DIY denitrator - I decided to build one and see if I could reproduce the results others were reporting.
I started with:
2 foot pieces of 4” PVC - 2
2 90 degree elbows
Various adapters and screw on cleanup fittings as can be seen in the photos.
A pump I had laying around
A gate valve
Some RO/DI tubing and random fittings to get the input line connected.
Media can be a little confusing - and easily the most expensive part of this. Various people use various things. Bottom line - you need something with a ton of surface area that won’t pack in so tight that it gets plugged up with bacteria slime.
I used 2 boxes of Ceramic rings - these are typically used in canister filters. https://www.amazon.com/gp/product/B000NRVLIU/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
A 8” X 8”X1” block of Marinepure ceramic biomedia - I bought 1 of these https://www.bulkreefsupply.com/marinepure-ceramic-biomedia-plate.html. This I broke up into random pieces.
1 1/2” Marinepure Ceramic Spheres - I bought 2 of these boxes https://www.bulkreefsupply.com/marinepure-ceramic-biomedia-1-1-2-spheres.html
I also pulled a couple small rocks out of my tank to help speed up the seeding of the new media.
Pictures work better than me trying to describe this - it’s pretty simple really. I have a cleanout one the top of the anaerobic chamber (output side) and a simple screw in fitting on the input side that allows me to dose a carbon source.
I drilled a 3/16” hole, roughly 2 inches down, on the side of each chamber. I drilled one about 1/2” lower than the other side. The lower side is the output - so anaerobic chamber - and the higher one is the input. In my photos the input is the blue RO line - the output is just a hole. I had RO/DI tubing in the hole but it kept plugging up with the bacteria slime. Since this whole thing is sitting in my sump - I decided to just let the output run down the side. Eventually I’ll drill a larger output hole, screw in some sort of fitting and put an actual output tube - many to help prevent slime buildup on the side.
I’m running a small, random pump that I had sitting around the house. No idea what it is, how much flow. I have plumbed this with a gate valve and bypass output which allows me to turn the flow down to literally a drip if I want without creating much back pressure on the pump. I’ll show this in pictures and hopefully a quick video as I won’t be able to describe it properly here.
So - what I have is a U shaped 4” PVC reactor (of sorts) with a small hole drilled in the side of each chamber, media filing the bottom half of the entire reactor. Pictures are easier than words for me so I’ll include them below.
You also need a carbon source. Use what you want - there are positives/negatives to any carbon source - honestly I don’t think it matters all that much - just pick what you want to use and use it. I use Red Sea NoPox - https://www.bulkreefsupply.com/red-sea-nitrate-phosphate-reducer.html . It works for me - again, use whatever you want.
I currently dose 6 ml per day - once a day - manually. Now that I know this setup will work I will implement a dosing pump for the NoPox and a smaller amount at least 2 or 3 times per day. This will also eliminate me missing days due to being forgetful.
I started running this around October 15. Took me a few days to get the flow dialed down to what was essentially a VERY slow but steady stream on the output side. I started dosing NoPox daily. I have NOT been religious about that though. We went on a cruise and were gone for 9 days and in all reality I probably dose 5 out of 7 days a week.
I knew things were starting to work due to the bacteria slime buildup in the output chamber. I’ve dosed carbon directly to the tank in the past and have experienced the bacteria bloom that is easy to get with that. I have NOT had a bacteria bloom in the tank or sump with this setup at all. Inside the output chamber is the only place I can see any of that slime. Photos below show the slimey goodness that many of us have seen throughout an entire tank when dosing carbon directly into the water column.
Roughly a month into this running I was able to measure my Nitrates down to 30 - 35 ppm Nitrates - they had been staying above 60 prior to this. Nothing else has changed. All good stuff, but not where I want my tanks to ultimately be.
About a week ago - holy cow, the STENCH - smelled like skimmate, kinda, but with a PUNCH. I’m talking - I walked into the house and could smell this stuff as soon as I opened the door. I knew it was coming from the tank area, I knew it smelled pretty much like skimmate, so I assumed it was my protein skimmer. I figured, hey, maybe it’s really pulling out a bunch of junk since I’ve got this denitrator working and I’ll just need to fashion up a skimmate locker with a carbon filter - THANKS to several members here for pointing me to that as a solution BTW. About a day later I decide “hey, I should look in the output side of that denitrator and see how much slime goo is in there”. MISTAKE, MISTAKE, MISTAKE!. I twisted off the cleanout plug from the anaerobic side and leaned over so I could look down into the chamber - I instantly understood EXACTLY where my new tank stench was coming from. HOLY COW - I can’t describe the smell that came out of there. I wish I could bottle it and send everyone some - it would be more effective than trying to describe it.
I knew I had read about the possibility of this - basically, if you don’t have enough nitrates in the anaerobic chamber the bacteria will find another food source and in doing so will produce hydrogen sulfide. I know it’s more complex than just that - but that is enough for us to understand that if your nitrates are too low you’ll eventually stink up your entire house. The good news is this is pretty easy to resolve. I simply increased the flow slightly and the stench went away within an hour.
This whole stanky house thing turned out to be a good thing. It prompted me to test my nitrate levels. I tested a sample that I pulled from the output of the denitrator and a sample of tank water. The results - were exactly what many others have experienced. While my tank levels are still fairly high - probably around 30 PPM or so - the levels coming out of the denitrator are well below 5 PPM. I always have to run my nitrate test diluted - on the high scale. Below, both samples are NOT diluted with RO. The sample on the left is 100% tank water pulled directly from my 60 gallon. The sample on the right is 100% water pulled directly from the output of the denitrator.
Bottom line - this thing is easy to build, can be done pretty cheap, easy to run - and it WORKS. I have some tuning to do for sure. Just like anything else in reefing there is going to be an art to tuning the dosing amount, schedule and flow through this thing to get nitrates at a nice low & steady amount.
Please feel free to ask any questions - I do NOT do a good job of writing things like this up, but I’m happy to offer up my experience with this so far.
