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

[olonmv]

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.

 

[Reeftank2008]

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

 

[olonmv]

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]

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

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

 

[Reeftank2008]

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

Yes the DND is in a shed outside.

 

[Reeftank2008]

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?

 

[Steve2020]

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?

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.

 

[Reeftank2008]

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

 

[Reeftank2008]

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

 

[Steve2020]

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.

 

[Reeftank2008]

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!

 

[Steve2020]

DND doing it's thing. Good amount of nitrogen gas being expelled. Very happy with how this thing is working.

 

[Reeftank2008]

I've just checked my no3 from dnd and it was 2.5ppm so it's coming down. Currently on 15ml dosing flow rate.... it was 25ppm yesterday so a good drop and taken approx 2/3 days to drop yo this value from increasing flow rate from 10ml to 15ml.

 

[olonmv]

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]

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.

 

[Reeftank2008]

I have today increased my flow through the dnd to 20ml per minute. The effluent was reading 0-2ppm on the outlet. I haven't tested my tank no3 yet but my goal would be to go back to how I initially started at 35ml per minute which is 10% of the tank...

 

[PeterEde]

I only just came to find this thread. Sadly I missed getting involved.
Donovan was so helpful to the community via this thread alone he helped many including me 5 years after his tragic death. RIP

 

[Steve2020]

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?

 

[Steve2020]

I just emptied each side of the DND. What I found was the aerobic side had a lot of whitish light tan slime but only about the first 8-12 inches and very light accumulation of slime the rest of the length of the tube. The anaerobic side had a pinkish slime that was very thick in a few areas but mostly light throughout the whole tube. What surprised me is that it was the larger media that accumulated the majority of the slime. The smaller media including the ceramic rings had very little slime so it looks like the larger media is what was causing clogging.
So, any thoughts or recommendations on why this happened with the larger media and should I just use the smaller media? I actually layered the large and small media and I am thinking if I mix up the media instead of layering it that it may work better as far as clogging.
I have the media separated by sides in buckets with salt water as we speak.
Thoughts?

 

[Reeftank2008]

Hi Steve

I can't really comment on why however I have experienced a similar scenario tonight that I have a white build up on my outlet?

Does anyone know if this is a good thing or bad thing? I haven't got any smell but I'm unsure if this means the flow is to slow however testing the nitrate I still have 10 nitrate coming out the DND?

If the slime is bacteria shouldn't the reading be zero? Or am I dosing too much carbon causing the bacteria slime?

Pic for reference.

Thanks Craig