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

wmb0003

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Could you explain to me the 15min check after dosing carbon? In my DND it takes 3.5-4hrs for inlet water to exit the DND. I am auto dosing 2.5ml every 3hrs. My DND is working fine but curious about your 15min rule.
It was a recommendation from Donovan to test if denitrification is happening. However, after finding his post he suggested 30 min. I would use his recommendation of 30 min instead of 15min.
A few recommendations:-

1) Your outlet pipe is too big, allowing air to enter the second chamber. We want air tight chamber here as denitrification happens at low oxygen

2) To test whether denitrification do happens, test the effluent output after 30 minutes vodka being dosed. If it is lower, test one more time after few hours and compare the differences.

3) If no NO3 reduction at item 2, reduce the flow to 25ml/10 seconds and repeat test no 2

* Please make the outlet hose smaller first :D
 

olonmv

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So I have slowed my flow down to 10ml per minute from 35ml per minute as still have the same nitrate reading.... I'm hoping this is enough to get it kick started....
I’m confident that you’ll get the DND to work with a slower flow but even if it does I’m afraid the size of your DND won’t turnover enough water at said flow rate to affect your volume of total water.
 
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olonmv

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If this works I will create a 3rd chamber of 3" pipe as I have some left.... if I do how big does the 3rd chamber have to be?

Thanks
Your total tank volume multiplied by .024 gives you volume of DND needed, assuming gallons as unit used. You’re currently trying to run one with a volume of 1.6gallons or so when I think in reality it should be in the 3.2gallon range.
What I did was get volume needed and then googled pvc volume calculator. You can plug and play different arrangement sizes and make one that suits your space. Don’t hold my thoughts as gold. I may be off. I scaled mine off of Donovan’s and pump water through my DND. I have a nano tank. My numbers are going down so I think it’s working. So maybe my numbers aren’t off. And for the sake of ease I used just one type of media.
 

olonmv

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So it's now in position is my destroyer and just doing some leak checks however can someone tell me do both sides of the reactor need to be sealed air tight or can the inlet side be a tight fit but not glued shut?

Thanks
16625805024521643518380248861481.jpg
Went back to look at your space. Are you trying to use the DND outside of a sump?
 
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Reeftank2008

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Well 17 days in and 1 days after turning the flow down I tested my outlet from DND and it was 0

My next question.... do I just increase the flow currently 10ml to 20ml and test again tomorrow? And I keep doing this until I get 10% turn over of the tank?

IMG-20220923-WA0017.jpg
 

Steve2020

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Well 17 days in and 1 days after turning the flow down I tested my outlet from DND and it was 0

My next question.... do I just increase the flow currently 10ml to 20ml and test again tomorrow? And I keep doing this until I get 10% turn over of the tank?

IMG-20220923-WA0017.jpg
You will probably get different recommendations but here is what I would do and what I am doing. First off lets say your NO3 goal for your tank is 5-7ppm NO3. I would slowly increase your flow every day or two until you see a slight increase in NO3 at the discharge of the DND. Once you see the increase I would back off the flow until you are back at 0ppm. Remember that your anaerobic bacteria will continue to multiply consuming more NO3. I would continue to increase and back off flow every few days until you reach the flow that gives you a consistent 0-1ppm NO3. Hopefully with your small DND you will get the flow your looking for and if not you may have to add that third tube you mentioned earlier. For simplicity reasons lets say you can achieve a 0-1ppm at 10% flow with your DND, the next steps would be to monitor your DND and tank NO3 levels. Once you see the tank levels dropping, it is time to determine the rate of decline of NO3 you want for your tank. I will use my tank as an example. The maximum daily I would drop the NO3 in my tank is 1-2ppm to start because I started at 19.6ppm with a goal of 5-7ppm. Once I get to 10ppm I would do one of two things or both and that is to increase flow and or decrease the carbon source until my DND discharge is at 2-3ppm NO3 monitoring my NO3 in my tank and DND every few days. The closer I get to my goal I am making small flow and or carbon dosing adjustments. Once you get to your desired tank NO3 levels you need to match the DND discharge NO3 to the tank NO3.
I know it sounds like a lot of monitoring and adjusting and it is but the last thing you want to do is take your NO3 DOWN TO ZERO IN YOUR TANK!!
One thing I am seeing with my system is my PO4 is also dropping at a fairly consistent ratio with my NO3 so you may want to monitor that also.
I am using the Hanna Checker for both my NO3 and PO4 and using API NO3 checker as a rough check. I have never had an issue with my Hanna Checker in almost 2 years and 100's of tests. Has always seemed to be very consistent.
Hope this helps you.
 
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Reeftank2008

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You will probably get different recommendations but here is what I would do and what I am doing. First off lets say your NO3 goal for your tank is 5-7ppm NO3. I would slowly increase your flow every day or two until you see a slight increase in NO3 at the discharge of the DND. Once you see the increase I would back off the flow until you are back at 0ppm. Remember that your anaerobic bacteria will continue to multiply consuming more NO3. I would continue to increase and back off flow every few days until you reach the flow that gives you a consistent 0-1ppm NO3. Hopefully with your small DND you will get the flow your looking for and if not you may have to add that third tube you mentioned earlier. For simplicity reasons lets say you can achieve a 0-1ppm at 10% flow with your DND, the next steps would be to monitor your DND and tank NO3 levels. Once you see the tank levels dropping, it is time to determine the rate of decline of NO3 you want for your tank. I will use my tank as an example. The maximum daily I would drop the NO3 in my tank is 1-2ppm to start because I started at 19.6ppm with a goal of 5-7ppm. Once I get to 10ppm I would do one of two things or both and that is to increase flow and or decrease the carbon source until my DND discharge is at 2-3ppm NO3 monitoring my NO3 in my tank and DND every few days. The closer I get to my goal I am making small flow and or carbon dosing adjustments. Once you get to your desired tank NO3 levels you need to match the DND discharge NO3 to the tank NO3.
I know it sounds like a lot of monitoring and adjusting and it is but the last thing you want to do is take your NO3 DOWN TO ZERO IN YOUR TANK!!
One thing I am seeing with my system is my PO4 is also dropping at a fairly consistent ratio with my NO3 so you may want to monitor that also.
I am using the Hanna Checker for both my NO3 and PO4 and using API NO3 checker as a rough check. I have never had an issue with my Hanna Checker in almost 2 years and 100's of tests. Has always seemed to be very consistent.
Hope this helps you.
Thanks for the detailed reply. I will start to monitor and adjust accordingly. Will report back
 

Steve2020

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So I just tested my outlet and the nitrate coming out the dnd was 25-50ppm @20ml flow rate.im going to back this off to 15ml now and see if this goes back to zero.

My display nitrate is 25ppm
One thing I forgot to mention is with your low flow rates make sure you keep an "eye ( nose ) out" for a rotten egg smell ( Hydrogen Sulfide ). If you get it you need to increase the flow and not worry about NO3. This could be a sign that your DND is to small and needs to be bigger to handle higher flow rates IMO.
 
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Reeftank2008

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One thing I forgot to mention is with your low flow rates make sure you keep an "eye ( nose ) out" for a rotten egg smell ( Hydrogen Sulfide ). If you get it you need to increase the flow and not worry about NO3. This could be a sign that your DND is to small and needs to be bigger to handle higher flow rates IMO.
Yeh I'm not getting any smells I do keep an eye out though. My wife would be the first to tell me if the tank stinks that's guaranteed!
 
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Congrats to the both of ya!!!! Glad to see results!
Mine have dropped down to 11.2 in display as of yesterday. Tried goin without mechanical filtration but I’m goin back. Too much free floating in water column for my liking. I have not gotten the sulfur smell nor the nitrogen bubbles which makes me doubt the test results but, I’m sure they’re correct. I’ve tested my sons tank and they were through the roof (it only housed a Galveston hermit crab who was very happy with the virtually no upkeep) on the same hanna batch of reagent. I’m leery of upping carbon dosage because I’ve seen a couple of small patch’s of cyano pop up and don’t want to fuel them with an over dosage of carbon. My flow varies from 8-15% daily turnover (3-5ish ml per minute) of tank volume. My second chamber in my AIO runs a small refugium with cheato that grows well on a 12 hr schedule with a cheato light, I also have removed a small bit of GHA but I feel that between the two its still not nearly enough to constitute a reduction in N03 that significant. I’ve done basically the same thing maintenance wise minus the DND and saw my numbers go from about the 9ppm range to 45ppm in a matter of a couple of months. I will test again today and see where the numbers are after taking Turkey baster to rocks for filtering and pulling bits of GHA. I suspect that since I only used one type of media that my DND isn’t as potent as it could be had I used various. Picked up some seachem matrix yesterday but looking for suggestions as far as if I’m missing something before disrupting the innards of my current setup.
 

Steve2020

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Congrats to the both of ya!!!! Glad to see results!
Mine have dropped down to 11.2 in display as of yesterday. Tried goin without mechanical filtration but I’m goin back. Too much free floating in water column for my liking. I have not gotten the sulfur smell nor the nitrogen bubbles which makes me doubt the test results but, I’m sure they’re correct. I’ve tested my sons tank and they were through the roof (it only housed a Galveston hermit crab who was very happy with the virtually no upkeep) on the same hanna batch of reagent. I’m leery of upping carbon dosage because I’ve seen a couple of small patch’s of cyano pop up and don’t want to fuel them with an over dosage of carbon. My flow varies from 8-15% daily turnover (3-5ish ml per minute) of tank volume. My second chamber in my AIO runs a small refugium with cheato that grows well on a 12 hr schedule with a cheato light, I also have removed a small bit of GHA but I feel that between the two its still not nearly enough to constitute a reduction in N03 that significant. I’ve done basically the same thing maintenance wise minus the DND and saw my numbers go from about the 9ppm range to 45ppm in a matter of a couple of months. I will test again today and see where the numbers are after taking Turkey baster to rocks for filtering and pulling bits of GHA. I suspect that since I only used one type of media that my DND isn’t as potent as it could be had I used various. Picked up some seachem matrix yesterday but looking for suggestions as far as if I’m missing something before disrupting the innards of my current setup.
If I remember correctly you are running a pressurized single tube DND. Don't quote me on this but it is a good thing not to have the rotten egg smell ( hydrogen sulfide ) and as far as nitrogen gas, I do not believe you will see the gas bubbles like in my system because the nitrogen gas is dissolved in the water and with no void space in your system the gas will not be removed from the water until it exits the DND. If the denitrification process is happening in your DND which it seems it is then you are producing nitrogen gas IMO.
As far as carbon source in your tank from the DND, to me that would mean you are dosing to much and the bacteria is not consuming most/all of it.
I am no expert at this to say the least so hopefully someone else will chime in with their opinion if they find my explanation incorrect.
 
AS

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This morning there was water coming out of the emergency drain. Opened the Aerobic side of DND and there is a massive amount of bacteria slime covering the media. Not sure why this happened since I am using large media. I was dosing 16ml DIY NoPox and seeded with MB7. I will be tearing it down today to see how far down the slime goes. Not sure if I did something wrong. Was working fine. Any Ideas on what might of caused this?
20220930_083247.jpg
 

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