Sulfur denitrator experiment

[Delphinus]

Not yet. Randy Holmes-Farley did this article about sulfur denitrators where he showed the chemical reactions happening and demonstrated how the calcium and alkalinity, although there will be some, won't really be a significant source for the tank. However I'm sure it's still better than having nothing.

Originally Posted by reeferaddict

gradually ramped it up to around the 5X media volume turnover per hour as stated in Delbeek and Sprung Vol 3

How did you ramp it up? I'm still running about one drop per 2 to 3 seconds. Could I start opening it up at this point?

I don't have vol3 yet. I dropped a pretty big hint to Santa though.

So ...

5x media volume. I'm using a 4" reactor and my media height is approx. 8.5".

So roughly PI * 2^2 * 8.5 (Pi * r^2, where r=2 because diameter is 4") = ~107 cubic inches

1 cubic inch = 16.387064 millilitres

Therefore 107 * 16.387064 = approx. 1750ml

1750ml * 5 = 8750ml/hour

8750 / 60 = approx. 145 ml/min

That seems pretty fast to me. Am I overlooking anything or should it really be opened up that fast?

I guess that's only about 6 seconds to fill a 15ml measuring spoon. A little more than twice what I run my calcium reactors at (I run mine at 60ml/min) so I guess it's maybe not that far off. Hmmm ... interesting.

Ok so the real question is how much time do I give myself to open up the reactor to that speed?

[christyf5]

Arggh math! My eyes!!!!!

I say damn the torpedoes! Full speed ahead!

Seriously though, that seems pretty fast, why not just try a fast drip for now, then ramp it up from there?

[Psyire]

I don't think you want to be increasing your drip rate...

You want a slow drip rate until you have enough bacteria to use up all the nitrate at that rate. Then you start increasing your drip rate slowly until you find the right rate for your current bioload. As your nitrate in the tank comes down you will further increase your drip rate until it is balanced at Zero nitrate in the tank, and zero coming from the reactor.

[Psyire]

2 weeks is too early to be jumping to conclusions and changing operation of your setup..

[Delphinus]

Be nice now. I'm not jumping to conclusions but I am questioning whether I should wait to see this thing help sort out an immediate situation I have right now.

3 months from now is practically March and that's a long way's away. Many things can happen in that timeframe.

As far as increasing the drip rate, I haven't. It doesn't make sense to me to start that until I see a NO3 reading on the output that's less than the input, because until then, there obviously isn't enough colonization to make the difference.

[Psyire]

Sorry, I didn't mean that in a 'not-nice' way.

Personally I would give it another week to see if anything changes. You should show a lower nitrate level by then I would think. 3 months seems like an aweful long time.

[Delphinus]

Day 23

Pheh, this is getting a little past ridiculous now.

I don't have a very good nitrite test kit, but I do have nitrate/nitrite test strips, which do at least confirm presence of nitrate and/or nitrite and useful for observing trends but I've found the numbers corresponding to the colour chart to be innaccurate so I don't use the test kit for determining absolute values.

However it does confirm the presence of nitrite in the reactor, and has been showing this for almost a week since I started using it. No reduction in nitrite level, in fact, the colour for nitrite is off the chart.

I last tested nitrate of the reactor at day 18 and it was still off the chart (i.e., >100ppm nitrate). However I wonder if a nitrite reading would throw off this reading. I haven't been able to procure a proper nitrite test kit, if I have time to pop into Gold's on Friday I'm picking one up (all other LFS's I've tried are either sold out or don't carry Salifert nitrite kits). However I'm somewhat leery of spending $30 on a test kit that I'll never again use after this little sulfur experiment...

I expected two outcomes - the first and more optimistic was that this would prove to be viable for me. The second and less optimistic was that it would still work, but the small volume of media I'm using would prove to be ineffective on a 115g overall volume of tank. Frankly I didn't expect at all that it would seem to be incapable of growing the requisite bacterial colonies and be completely ineffectual as a result. I'm now wondering if there is something about how I've set it up, that is incorrect, or perhaps sub-optimal for running a sulfur reactor. I really wish I could see a working model in person .. I'm basically at a loss.

In the last week, I have run two 25% water changes (I don't really have the means to do a water change larger than 30 gals, I don't have a large enough reservoir to make more makeup SW) and that should put the tank nitrate level to approx. 40ppm from the initial 75ppm (75% of 75ppm =~ 56 ppm, 75% of 55ppm =~ 42 ppm), I've also moved my mangroves over and planted them in the remote-DSB, I've also made a chaeto cage and moved some chaeto onto this tank so I'm now throwing all I've got at this tank in an effort to get the nitrates down to a tolerable level .. there is a point of diminishing returns though and I don't mind admitting that I wish this sulfur reactor would kick in at some point. 3.5 weeks and no positive trend yet ... well we'll see where this goes. Maybe it's just me, and it's just not going to work. I'll give it a few more weeks but I guess there's no point in more updates at this point until there's actually a change to report on.

[christyf5]

Sorry to hear Tony, I had such high hopes that this would be the solution

[Delphinus]

Me too. Yeah, I dunno. I don't know what to do. Maybe the commercial units have bigger pumps, or have an upwards flow through the media. Maybe there's a threshold volume of media that's needed and I just don't have it. Who knows. If I could see a working and proven unit in action I could compare notes... Oh well.