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

[Reeftank2008]

I'm still no further in reduction yet....

 

[olonmv]

I'm still no further in reduction yet....

How fast is your flow? Mine is literally dripping (I run a nano). What did you use to seed the DND? Posters on here have had no luck with dr Tim’s in getting their device seeded.

 

[Reeftank2008]

I used seachem stability, zeobak and fm bacto so abut of them all. I'm using fm bacto energy and kz zeostart 3 as the carbon source....

 

[Reeftank2008]

It's also just a drip (35ml /min)

 

[olonmv]

I used seachem stability, zeobak and fm bacto so abut of them all. I'm using fm bacto energy and kz zeostart 3 as the carbon source....

Maybe someone can chime in on those bottled bacs as Im not very familiar with the types of bacteria in them. What seems to be the one that works well is MB7 to seed which is the route I went (I had a half bottle of the stuff already) and carbon doses with 80 proof vodka. Bought the cheapest smallest bottle they had and seeded for 5-6 days and started vodka on the 3rd. I did up my dose from .8 to 1ml after day 7 of initial dose or so.

 

[olonmv]

It's also just a drip (35ml /min)

What’s your tank volume?

 

[Reeftank2008]

What’s your tank volume?

500 litre approx 100gal

 

[Steve2020]

What’s your tank volume?

What’s your tank volume?

I believe in a previous post he said his volume is 500L which 35ml/min would would equate to the 10% daily exchange rate.

 

[olonmv]

I believe in a previous post he said his volume is 500L which 35ml/min would would equate to the 10% daily exchange rate.

I’m gonna be honest. I think your DND might be undersized. 132 gallons (total volume I’m assuming) is your volume in gallons, you need a DND to accommodate 3.2 gallons when dry (no media). Your current one is under 2 gallons. You need either 48” long or a 24” double rise in 4” PVC. Someone check me please. Or try slowing flow down.

Edit: sorry, I meant to respond to @Reeftank2008 . I feel that His DND is undersized so his flow needs to be reduced but you’re correct, 35ml per minute is what I get as flow rate for one that I think is the correct size.

 

[Reeftank2008]

I started the DND up on 7th September so I'm approx 12 days in. I'm reading it can take 4 weeks to kick in? That right?

 

[olonmv]

I started the DND up on 7th September so I'm approx 12 days in. I'm reading it can take 4 weeks to kick in? That right?

Your DND has a volume capacity when dry of 1.24 gallons. I think you need to be able to hold about 3.2 gallons. In retrospect, Donovan’s holds 1.958 gallons when dry. He has an 80 gallon tank. Yours is more than 1 1/2 times bigger than his yet your DND is smaller. You can always try slowing down flow more. I’m not sure if that would suit your tank volume though.

 

[Reeftank2008]

Your DND has a volume capacity when dry of 1.24 gallons. I think you need to be able to hold about 3.2 gallons. In retrospect, Donovan’s holds 1.958 gallons when dry. He has an 80 gallon tank. Yours is more than 1 1/2 times bigger than his yet your DND is smaller. You can always try slowing down flow more. I’m not sure if that would suit your tank volume though.

So the reactor may not be big enough but surely the outlet would be zero? I'm currently turning over 10% of the tank which isn't much?

 

[Steve2020]

"So the reactor may not be big enough but surely the outlet would be zero?"
Not necessarily. If your DND is not big enough you may not be eliminating the O2 to grow anaerobic bacteria which as you know is the bacteria that consumes the NO3. If this is the issue, you may see an increase vice a decrease in NO3 at the discharge of the DND.

 

[olonmv]

I’m not sure the outlet would be zero for a DND that size at that flow rate. I’d imagine it to be too fast.

 

[PeterEde]

Is this how ZeoVit works? but a cheaper option and probably more effective? lol

Or a Sulphur reactor

 

[Reeftank2008]

I'm thinking I may need to go sulphur reactor is this is the case as I can't really make this unit any bigger....

 

[wmb0003]

I'm thinking I may need to go sulphur reactor is this is the case as I can't really make this unit any bigger....

Have you compared the tank water vs the outlet of the DND? You need to measure nitrates in the outlet of the DND 15 mins after you have dosed the carbon source. If there is not a difference, there might be a problem with the bacteria population.

 

[Steve2020]

Have you compared the tank water vs the outlet of the DND? You need to measure nitrates in the outlet of the DND 15 mins after you have dosed the carbon source. If there is not a difference, there might be a problem with the bacteria population.

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.

 

[wmb0003]

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

 

[Reeftank2008]

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....