remote deep sand bed for no3/po4

[davidwillis]

I did start vinegar dosing several weeks, maybe a month before I started the sand, but I have not made any changes to the amount since starting.

 

[Miami Reef]

I did start vinegar dosing several weeks, maybe a month before I started the sand, but I have not made any changes to the amount since starting.

How much vinegar (in mL) per how many gallon system?

 

[davidwillis]

200 ml in a 300 gallon tank (17ml per 25 gal), which is at the week 5 level on the chart I follow. It goes up to 61 ml/25 gal at week 16, but I stoped increasing at week 5 when I started the sand bed. At that point I had not noticed any reduction in no3. But as I mentioned earlier, the reduction could very well be due to the carbon dosing.

 

[davidwillis]

Start No3: 35.6
one week No3: 30.9
two weeks No3: 23.6
three weeks No3: 22.5
four weeks No3: 22.2
five weeks No3: 21.5
six weeks No3: 6.3
seven weeks No3: 17.4

 

[John K]

Wow! That’s awesome results! Did you add any organic carbon (vodka, vinegar, sugar etc) to spur denitrification?

Careful mixing methods / processes.

Denitrification is bacteria breaking nitrate down. OC additions drive bacterial growth, which then fixes nitrate and phosphate into biomass. OC dosing reduces nitrate, but in a different way.

 

[Miami Reef]

Careful mixing methods / processes.

Denitrification is bacteria breaking nitrate down. OC additions drive bacterial growth, which then fixes nitrate and phosphate into biomass. OC dosing reduces nitrate, but in a different way.

Incorrect. Denitrification REQUIRES an organics to complete the process of reducing nitrate into nitrogen gas:

Here’s the equation by Randy Holmes-Farely:

organic + 124 NO3– + 124 H+ → 122 CO2 + 70 N2 + 208 H2O

 

[jda]

The anaerobic bacteria need some sort of negatively charged electron donor which does not really appear to be an issue in our tanks - the electron donor is kinda like FREE in BINGO or R, S, T, L, N and E in Wheel of Fortune. Organics certainly work as the electron donor.

You can mix OC and still have anaerobic bacteria as long as there is no3 present. The bacteria that we create with OC might not even use no3 - they might gobble up nh4 or no2 and the no3 is lowered by a lack of incoming - we just don't know, right? There is no telling which form of bacteria choose to grow. We do know that anaerobic bacteria do need no3 and probably the only thing in our tanks that actually does.

It doesn't sound like the OC did much, anyway. The dose should have done something in that amount of time. Hard to know that it did nothing until it is stopped, but with no3 lowering at a steady pace, I would not change anything.

 

[davidwillis]

Start No3: 35.6
one week No3: 30.9
two weeks No3: 23.6
three weeks No3: 22.5
four weeks No3: 22.2
five weeks No3: 21.5
six weeks No3: 6.3
seven weeks No3: 17.4
eight weeks No3: 19

 

[davidwillis]

Start No3: 35.6
one week No3: 30.9
two weeks No3: 23.6
three weeks No3: 22.5
four weeks No3: 22.2
five weeks No3: 21.5
six weeks No3: 6.3
seven weeks No3: 17.4
eight weeks No3: 19
nine weeks No3: 16.8

 

[davidwillis]

Here are a couple of updates... to changes I have made in my tank.
1- I have reduced carbon dosing by about 1/2 (mainly to try to get my ph up). I did this a couple of weeks ago, sorry I should have mentioned it.
2- My flow through my buckets has slowed. The pump I was using was not very powerful, and could not push water through the 5 micron filter very well. I also need to change the filter, but I just put on a larger pump, and am getting good flow now, so I will wait to change the filter for a few more weeks.

So the low flow, or maybe the reduced vinegar may have been the reason it is not dropping fast (or came up from 6.3, if that was an accurate test). I am leaving the vinegar dosing the same, but now have the flow up, and will see what happens.

 

[davidwillis]

Start No3: 35.6
one week No3: 30.9
two weeks No3: 23.6
three weeks No3: 22.5
four weeks No3: 22.2
five weeks No3: 21.5
six weeks No3: 6.3
seven weeks No3: 17.4
eight weeks No3: 19
nine weeks No3: 16.8
Ten weeks No3: 14.8

This week I had some issues with my vinegar dosing. I had filled the jug back up, but forgot to turn the valve back on, so I did not dose any vinegar for a few days. I noticed something was strange when my skimmer stopped skimming. Once I started dosing again, the skimmer started working again.

This week I was expecting my no3 to go up, since I went several days without dosing, and about 36 hours without my skimmer doing anything.

 

[jda]

Over 50% reduction in 10 weeks is impressive. The steady decline is solid. My guess is that the remote DSBs are taking over as you scaled back and then stopped the OC for a bit. Time will tell.

You have a target for where you stop with the vinegar all together, or are you going to keep it up?

 

[davidwillis]

Over 50% reduction in 10 weeks is impressive. The steady decline is solid. My guess is that the remote DSBs are taking over as you scaled back and then stopped the OC for a bit. Time will tell.

You have a target for where you stop with the vinegar all together, or are you going to keep it up?

Yes, that sounds like a good guess, and what I am also thinking. I want to keep nitrates between 5-10, so if they consistently stay under 10, I will reduce more. I don't mind dosing vinegar, but I don't like it at such a high dose that I coat everything in bacteria (I am not seeing that with the current level).

 

[davidwillis]

Start No3: 35.6
one week No3: 30.9
two weeks No3: 23.6
three weeks No3: 22.5
four weeks No3: 22.2
five weeks No3: 21.5
six weeks No3: 6.3
seven weeks No3: 17.4
eight weeks No3: 19
nine weeks No3: 16.8
Ten weeks No3: 14.8
eleven weeks No3 19.5

I think it is clear that the 3 buckets of sand was able to reduce the nitrates from 35 to 20, and it only took about 3 weeks to get there. It may slowly creep down more, but I think that is about the limit, and I will need to add more buckets if I want it lower. I was a little worried with 35-40, but at the 14-20 range I feel fine.

 

[jda]

IME it takes 6-7 months for a DSB to really take off. I have only done them in tanks and no idea if buckets are different, but I would not be shocked if they were not done yet.

 

[davidwillis]

IME it takes 6-7 months for a DSB to really take off. I have only done them in tanks and no idea if buckets are different, but I would not be shocked if they were not done yet.

Interesting... I will try not to make any big changes, and see if it keeps going down.

 

[DCR]

I think you have proven out the concept. Those three five-gallon buckets on a 300-gallon tank are not going to offer nearly as much surface area for water diffusion down into the sand as a large tank with a 3" bed. I think the surface area is more important than the total volume of the sand. I was impressed with the results that you have achieved thus far with those buckets. I would look at upgrading those with a shallow tank like a 60 breeder or something similar in a plastic container or even a 125 gallon if you want to get really now numbers.

 

[davidwillis]

I think you have proven out the concept. Those three five-gallon buckets on a 300-gallon tank are not going to offer nearly as much surface area for water diffusion down into the sand as a large tank with a 3" bed. I think the surface area is more important than the total volume of the sand. I was impressed with the results that you have achieved thus far with those buckets. I would look at upgrading those with a shallow tank like a 60 breeder or something similar in a plastic container or even a 125 gallon if you want to get really now numbers.

From what I have read, the depth is more important than surface area. It is the lower levels that use up the nitrates, not the top. I would not do it in anything less than 8" and not more than 12". I think a 60 breeder or 125 would work great.

 

[BeanAnimal]

I think you have proven out the concept. Those three five-gallon buckets on a 300-gallon tank are not going to offer nearly as much surface area for water diffusion down into the sand as a large tank with a 3" bed. I think the surface area is more important than the total volume of the sand. I was impressed with the results that you have achieved thus far with those buckets. I would look at upgrading those with a shallow tank like a 60 breeder or something similar in a plastic container or even a 125 gallon if you want to get really now numbers.

I don’t think that I agree with this. Depth and volume appear to be the driving factor. Where do diminished returns start? That I do not know.

My big question has always been are we actually removing or simply sequestering.

It matters because the former is an endless filter and the later a ticking time bomb where buckets need to be removed on a cycle and replenished with new sand.

 

[jda]

We don't know if my larger sandbed is fully saturated with the bacteria or at 1%. Nobody knows the capacity of a certain area. The depth of those buckets could be many times their surface area. I have seen a few buckets keep no3 in large tanks down, it just takes a while to develop.