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

[Lasse]

I would avoid siporax in a denitrator - please see here and some pages forward



Sincerely Lasse

 

[Tritie]

I would avoid siporax in a denitrator - please see here and some pages forward



Sincerely Lasse

I don't have a problem with silicates. In fact, the Siporax has been there for over a year and my silicates were always absent on ICP. That is until I started dosing silicates to force a diatom bloom for a dino problem. It didn't work, I had over 12ppm of silcate for months and no diatoms. I stopped dosing and now my silicates are down to 10.7 with just normal water changes. The siporax is still in there. I am confident in saying it has no significant impact to the amount of silicate in my system.

 

[Lasse]

The siporax is still in there. I am confident in saying it has no significant impact to the amount of silicate in my system.

It is a difference if you have your siporax in aerobic or anaerobic environment. It is also my experiences that siporex in aerobic environment (there is oxygen gas present) will not leak any silicates but in a denitrator ( like the one in this thread) the environment is anaerobic (no oxygen gas present) and in this case - it leaks a lot of silicates - see my ICP tests below

Sincerely Lasse

 

[Tritie]

It is a difference if you have your siporax in aerobic or anaerobic environment. It is also my experiences that siporex in aerobic environment (there is oxygen gas present) will not leak any silicates but in a denitrator ( like the one in this thread) the environment is anaerobic (no oxygen gas present) and in this case - it leaks a lot of silicates - see my ICP tests below

Sincerely Lasse

Interesting. I'll still give it a shot, but I'll put it in the beginning line-up. Thank you for clarifying this!

 

[stambo3]

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 140g (3’7''x2’4''x2’4'') Coral Reef Aquarium 11 months ago. With a huge fish load and heavy feedings, I’ve climbed to about 100+ nitrates And holding steady there. Fishes are acting fine . So I wanted to keep nitrates down since I can’t do massive water changes (no room for 20 gallons water tanks). I haven't done a water change in 2 months.

So about 3 weeks ago, I put in-line the DND and started dosing MICROBE-LIFT Special Blend 118ml for a week along with 6mL vodka daily . Took about 1 weeks to see the effluent nitrate level drop to 0. Took about 2 weeks to see the nitrate level in the tank dropped to 1-5 ppm and stayed there. I stopped dosing vodka. I only have LPS and soft corals. They weren't happy at first, but when the system settled in, they all began to visibly grow.
Copied part of the text from "Joj" / accept my thanks / because I don't know English and I use Google translator, for which I ask you to forgive.

 

[Keecha]

Hi,

I completely read through this topic several weeks ago with great anticipation. I was then shocked to read that Donavan is no longer with us. May he rest in peace.

My adventure with my reef (185g/700 liters) started exactly 1 year ago tomorrow. Meanwhile, I have been suffering from too high nitrate (130-160) for several months. Due to a faulty test set I was unaware of any harm and let it get too far. After the loss of a couple of corals I find out there was something wrong. I tried many things (cheato, caulerpa, self made NoPox, sulfur,...), but without success. Then I had landed on this topic....

2 weeks ago I built my own Donovan's Nitrate Destroyer (4 inch/10 cm diameter, 20 inch/50 cm hight). I used ceramic rings and filter substrate to fill the tubes. Dosed bacteria for the first 5 days and VSV from day 3 (started with 5ml, now 12ml through a doser) After a few days the outlet was already running less smoothly and slime was coming out. So I thought this will work, the bacteria are multiplying and my nitrate will go down in no time. Not yet ....

Yellow tube: Manual input for bacteria
Pink tube: automatic VSV dosing
Clear tube: tank water from the return manifold
White tube: output in return chamber

Last Thursday I did a test of the water coming from the destroyer, and I noticed a reduction. Since the water was only coming out drop by drop and sometimes it didn't run at all, I accelerated it to a ticker stream. Also because I read that the last chamber needs to be air tight. However, the nitrate value from the destroyer has increased again and I am not getting any other results. Not even when I test after waiting 30min between dosing VSV.

Have I done something wrong or overlooked something?
Other in this topic had some results after two weeks, or am I
I would love to have some advice from people who have run a successful destroyer.
Thanks in advance for the necessary feedback!

 

[blazn]

Your system/design looks good. The fact that you've identified that your reactor was reducing NO3, at least at one point, would indicate that you're on the right track. It took me 49 days to get my DT NO3 down from 75 to 13 using my 'destroyer'. You basically need to 'play round' with the flow rate and carbon dose until it starts reducing your DT NO3, at which point you'll be able to reduce one or both for a maintenance level. I use only vodka and started with 5ml/day, ramped up to 20ml/day at the peak and after reducing my DT NO3 to around 10, I'm maintaining it at 4ml/day (on a 120g DT with 55g sump). As it apparently takes a higher dose of vinegar to match the results of vodka, I'm assuming it would be similar for VSV, but I haven't used VSV. I would expect you may need to increase your carbon source, and possibly slow your flow, especially as your system is 50% larger than mine, but your mileage certainly may vary.

Just be patient with it and keep tweaking your input/output as necessary. You'll get there and you won't have to worry about those high NO3 levels again.

 

[Keecha]

Your system/design looks good. The fact that you've identified that your reactor was reducing NO3, at least at one point, would indicate that you're on the right track. It took me 49 days to get my DT NO3 down from 75 to 13 using my 'destroyer'. You basically need to 'play round' with the flow rate and carbon dose until it starts reducing your DT NO3, at which point you'll be able to reduce one or both for a maintenance level. I use only vodka and started with 5ml/day, ramped up to 20ml/day at the peak and after reducing my DT NO3 to around 10, I'm maintaining it at 4ml/day (on a 120g DT with 55g sump). As it apparently takes a higher dose of vinegar to match the results of vodka, I'm assuming it would be similar for VSV, but I haven't used VSV. I would expect you may need to increase your carbon source, and possibly slow your flow, especially as your system is 50% larger than mine, but your mileage certainly may vary.

Just be patient with it and keep tweaking your input/output as necessary. You'll get there and you won't have to worry about those high NO3 levels again.

Thanks for the confirmation and the fact that indeed it just takes more time .
You automatically start comparing systems to each other even though they are very different.
Yesterday I also bought an extra valve to better manage the incoming flow. I will then indeed play around with the input/output/VSV dosing.

 

[blazn]

Thanks for the confirmation and the fact that indeed it just takes more time .
You automatically start comparing systems to each other even though they are very different.
Yesterday I also bought an extra valve to better manage the incoming flow. I will then indeed play around with the input/output/VSV dosing.

Getting a precise enough input valve (without spending $100+) is probably the most challenging part of the design, at least that's my experience. Once you get thru the initial stage and get it 'dialed in', it's pretty much on auto-pilot. Keep at it and you'll get there.

 

[JGT]

Interesting read. Question which might be answered somewhere in this thread is are the caps for each tower permanently glued or just snapped on? As there’s talk about pressurizing the towers I’m thinking the former.

 

[blazn]

I imagine that you could glue the caps, but I don't, mine just press down into place and it would take quite a bit more water pressure than exists to force them out. I wouldn't want them glued, as you'll most likely need to get inside at some point down the line.

 

[JGT]

I imagine that you could glue the caps, but I don't, mine just press down into place and it would take quite a bit more water pressure than exists to force them out. I wouldn't want them glued, as you'll most likely need to get inside at some point down the line.

OK, that was my take as well. Having access to the insides would be useful. Thanks.

 

[Levinson]

I don't use Donnovan's nitrate destroyer(DND) but have always been fascinated by the idea for a while.
This might have been asked before but what happens if the tank with the DND has been stripped of nutrients? Do you just leave it running? Does it produce unwanted gas like sulfate if there's no nutrient left to process?

 

[blazn]

If a DND was to remove all nutrients, the carbon source can be discontinued, as at least one prior person had indicated that is how their DND experience 'evolved'. At that point, it would be like any bio-block or live rock you'd have in your sump. You either increase nutrients (feeding) or remove some of the filtration. I would expect that typically, those with high enough NO3 to build & utilize a DND would have enough nutrient input (heavy feeding, etc) that it would not end up stripping out all nutrients, as long as the carbon source is reduced and possibly eliminated, if needed. I would not expect any sulfate gas to be produced if the carbon source was reduced to a minimum or eliminated. I dose 4-5ml of vodka/day in my DND and never have any noticeable gas/slime output.

 

[twentyleagues]

I don't use Donnovan's nitrate destroyer(DND) but have always been fascinated by the idea for a while.
This might have been asked before but what happens if the tank with the DND has been stripped of nutrients? Do you just leave it running? Does it produce unwanted gas like sulfate if there's no nutrient left to process?

Well thats the thing is you dont want to strip the tank of all n and p. Thats why you monitor it control flow and input of carbon. When you get to your desired level you just need to figure out the maintenance dose and flow.

 

[Keecha]

I have been running the DND for 4 weeks now. And I am really amazed at the results today.
Past 2 weeks regularly tested the output and adjusted the flow and VSV dosage and this has now paid off.
4 days ago my nitrate coming out of the reactor was still 50/100, today 5 !!!
I still have a long way to go before the whole aquarium is at this value, but now there is light at the end of the tunnel

4 Days ago (left) and today (right):

 

[blazn]

I have been running the DND for 4 weeks now. And I am really amazed at the results today.
Past 2 weeks regularly tested the output and adjusted the flow and VSV dosage and this has now paid off.
4 days ago my nitrate coming out of the reactor was still 50/100, today 5 !!!
I still have a long way to go before the whole aquarium is at this value, but now there is light at the end of the tunnel

4 Days ago (left) and today (right):

Awesome! It sure does feel good once you know you can take control of your NO3 level!!

 

[Levinson]

I will be connecting a new peppermint shrimp grow-out tank to my current tank and I plan on adding DND to the system but more on that in the future.

This post is about a random thought about a different passive version of DND that came to mind today and I wanted to hear your opinions on it.
The idea is to have it just sit inside of a tank (or any place with water depth) with relatively high flow. The only oxygen that will get inside of the chamber will be the dissolved oxygen in water that will enter from the bottom of the chamber since the upper part will be sealed off. The oxygen in water should be lower closer to the top. If an anaerobic zone can be formed, any gas that is formed should be able to escape upwards through the check valve on top while remaining sealed from the air outside.
Not sure the flow outside would impact the water movement inside the chamber.
This requires some depth of water (if it even works) and there's not much you can control.
This isn't what I plan on having in my new setup (not at the moment anyway). It's just a random thought for fun.

 

[Levinson]

So I'm planning on building a DND.
Currently, I've got a 110 litre (about 30 gallons) tank but I will be connecting another 110 litre tank to it (it will be a shrimp grow-out tank), so it'd be around 60 gallons total.
So far I've got 3 designs in mind, trying to decide which one to go for. The differences are more about where and how I will place the DND.

1. DND inside the tank

Keeping it inside will take the tank space and it won't look great but it'd be straightforward and I'd feel much safer about any potential leaks though unlikely.

2. DND outside the tank

This doesn't take the space inside the tank but I have to build a platform for it to stand on. My tank is made of aluminium extrusion so I was thinking 90 angle brackets bolted onto the side of the tank stand and placing a wooden board on top as the platform. The downside is the space between the tank and the wall is workable but kind of narrow so installation and any maintenance involved will be bothersome. Plus, I'm paranoid about 'what if it leaks'.

3. Very tall DND outside the tank

This design is too big for my setup but I can just have less bio filter media in it. The picture is showing much smaller pipe on the inlet side (so without any media in it) but this is just because I thought the second pipe had enough space for the anaerobic zone to form and thought it didn't really matter if I used bigger pipes on both sides or not. I could always put in more media or take some out.

I'm leaning towards the first option at the moment but I change my mind about it quite often.
Any inputs, suggestions, or thoughts are welcome.

 

[Levinson]

It is a difference if you have your siporax in aerobic or anaerobic environment. It is also my experiences that siporex in aerobic environment (there is oxygen gas present) will not leak any silicates but in a denitrator ( like the one in this thread) the environment is anaerobic (no oxygen gas present) and in this case - it leaks a lot of silicates - see my ICP tests below

Sincerely Lasse

That's a pity. I have quite a bit of siporax lying around and I was planning on using them for my DND. Now I'll only be able to use some in the aerobic zone closer to the inlet.
I dose silicate to my tank on a regular basis for my sponges but the leak seems like too much.
Do you reckon I could throw in just a few pieces of siporax in the DND anaerobic zone and let it leak out silicate just a little? Like a reactor? Or is it too risky?