Not all Cycling Bacteria are created equal. Who's who, and what do they need?

[taricha]

One Last update to the Biospira Temp extreme side quest
(earlier results below)

The Biospira sample that got a single "hard freeze" in 15mL centrifuge tube overnight in the freezer at 0F - actually ended up processing ammonia AND nitrite just fine, it was merely significantly delayed. See Yellow data below.

The amount of NO2-N accumulation is clearly lower than the ammonia-N consumed (like the other biospira samples) - indicating plenty of active nitrite oxidizers in this sample too. In fact, although the onset of ammonia processing was delayed by ~7 days, after that - the rate of ammonia consumed and nitrite produced looks almost identical to rate of the other active samples.
The sample that got 3x cycles of hours to overnight hard (0F) freezes and thaws still looks dead by comparison.

The additional result is that even the biospira sample that got hard frozen (0F) overnight, thawed, shaken refrozen, thawed.... 3 cycles of hours of deep freeze at 0F and full thaw and mixing.... still processed ammonia AND nitrite.
See purple data below.

It looks like by day 17 or 18, the survivors in the sample that had been hard frozen 3x had recovered in population enough to begin visibly oxidizing ammonia and nitrite. The control that got nothing still left ammonia untouched.

Sometimes @Dan_P and I can sound like Biospira fanboys....but, good grief. The stuff is instantly active, fast working, and virtually un-killable.

I know it's a terrible business idea to tell the customer your product can't fail, but I'd be super tempted to print "idiot proof and unkillable" on the bottles.

 

[Dan_P]

One Last update to the Biospira Temp extreme side quest
(earlier results below)




The additional result is that even the biospira sample that got hard frozen (0F) overnight, thawed, shaken refrozen, thawed.... 3 cycles of hours of deep freeze at 0F and full thaw and mixing.... still processed ammonia AND nitrite.
See purple data below.

It looks like by day 17 or 18, the survivors in the sample that had been hard frozen 3x had recovered in population enough to begin visibly oxidizing ammonia and nitrite. The control that got nothing still left ammonia untouched.

Sometimes @Dan_P and I can sound like Biospira fanboys....but, good grief. The stuff is instantly active, fast working, and virtually un-killable.

I know it's a terrible business idea to tell the customer your product can't fail, but I'd be super tempted to print "idiot proof and unkillable" on the bottles.

That does it. I am getting a BioSpira t-shirt.

Isn’t this the product Dr Tim developed for Instant Ocean?

 

[taricha]

That does it. I am getting a BioSpira t-shirt.

Isn’t this the product Dr Tim developed for Instant Ocean?

yep, he did. That has come up on the forums a few times.

 

[taricha]

Group 4: This essentially ends the screening of bacterial products vs ammonia-only in the dark.
(Group 1 samples are here in post 44, Group 2 samples are in post 63, Group 3 in post 139 )

Here's Group 4 - the next 10 samples:

1 - Tank Water: inoculated with a drop of water from my tank.
(this serves as a negative control like in the earlier groups.)
2 - Frtitz Turbo Start 900: This is the positive control for group 4

3 & 4 a second bottle of Dr. Tim's One and Only: after the slow performance of One and Only in group 2 results, I wanted to see how a second bottle from a different store would compare under essentially the same conditions.

5 & 6 - StartSmart: This is a kind of gimmicky sounding one that my LFS has a ton of bottles of for cheap. There's a few things that raise my eyebrows. "Treats freshwater or saltwater aquariums... Cleans and clears water...Reduces scum...
Cycles ammonia, nitrite, and nitrate out of water" (denitrification?)
"Instantly cycles a new or problem aquarium...Comes in freshwater and saltwater versions...Converts toxic ammonia into nitrite then into nitrate instantly when used as directed" (sounds pretty magic, or at least like chemical oxidation, and not very bacterial).
There's also an MSDS with an interesting list of specific bacteria in their products...
"Bacillus licheniformis, ATCC 12759
Bacillus amyloliquefaciens, ATCC 23842
Bacillus subtilis, ATCC 29056
Pseudomonas stutzeri, ATCC 11607
Nitrobacter winogradskyi, ATCC 25391
Nitrosomonas europaea, ATCC 25978
The listed bacteria are each found in all Liquid-Based Bacterial formulations (listed above). The exact concentration, ratio, and mix of each bacterial species depends on the formulation and is proprietary"
(The last two would be the expected traditional nitrifiers)

7 & 8 - Fluval Cycle: "Add Fish Immediately...Eliminates ammonia and nitrite...For use in freshwater and saltwater aquariums"

9 & 10 - The Worst Petco "Live" Rock I could find:
I got a piece that looked totally raw like a hunk of white ceramic sprayed pink/purple. I broke chunks off of it and used that as the starting material for samples 9 and 10. This could be thought of as a baseline for a very low quality material that has nothing going for it except it was in a live system with fish etc.

 

[Dan_P]

Group 4: This essentially ends the screening of bacterial products vs ammonia-only in the dark.
(Group 1 samples are here in post 44, Group 2 samples are in post 63, Group 3 in post 139 )

Here's Group 4 - the next 10 samples:

1 - Tank Water: inoculated with a drop of water from my tank.
(this serves as a negative control like in the earlier groups.)
2 - Frtitz Turbo Start 900: This is the positive control for group 4

3 & 4 a second bottle of Dr. Tim's One and Only: after the slow performance of One and Only in group 2 results, I wanted to see how a second bottle from a different store would compare under essentially the same conditions.

5 & 6 - StartSmart: This is a kind of gimmicky sounding one that my LFS has a ton of bottles of for cheap. There's a few things that raise my eyebrows. "Treats freshwater or saltwater aquariums... Cleans and clears water...Reduces scum...
Cycles ammonia, nitrite, and nitrate out of water" (denitrification?)
"Instantly cycles a new or problem aquarium...Comes in freshwater and saltwater versions...Converts toxic ammonia into nitrite then into nitrate instantly when used as directed" (sounds pretty magic, or at least like chemical oxidation, and not very bacterial).
There's also an MSDS with an interesting list of specific bacteria in their products...
"Bacillus licheniformis, ATCC 12759
Bacillus amyloliquefaciens, ATCC 23842
Bacillus subtilis, ATCC 29056
Pseudomonas stutzeri, ATCC 11607
Nitrobacter winogradskyi, ATCC 25391
Nitrosomonas europaea, ATCC 25978
The listed bacteria are each found in all Liquid-Based Bacterial formulations (listed above). The exact concentration, ratio, and mix of each bacterial species depends on the formulation and is proprietary"
(The last two would be the expected traditional nitrifiers)

7 & 8 - Fluval Cycle: "Add Fish Immediately...Eliminates ammonia and nitrite...For use in freshwater and saltwater aquariums"

9 & 10 - The Worst Petco "Live" Rock I could find:
I got a piece that looked totally raw like a hunk of white ceramic sprayed pink/purple. I broke chunks off of it and used that as the starting material for samples 9 and 10. This could be thought of as a baseline for a very low quality material that has nothing going for it except it was in a live system with fish etc.

Off the wall questions for you.

Which bottled ammonia oxidizing bacteria product produces the worst case of the uglies? Does the size of the population of AOB affect how bad the uglies become in a new system?

 

[taricha]

Off the wall questions for you.

Which bottled ammonia oxidizing bacteria product produces the worst case of the uglies? Does the size of the population of AOB affect how bad the uglies become in a new system?

On the one hand, I have no uglies+nitrifier-growth-experiments that would give me any direct basis to answer this. But let me make up a very speculative response based on some data in this thread anyway...

If I wanted to cycle a tank with ammonia oxidizers and still grow a bunch of uglies, I'd pick Fritz. Here's why: the curve shape for Fritz against ammonia concentration is unique - it's extremely flat at low concentrations of ammonia.....

Note how Fritz really drops to a crawl at low amounts of ammonia <0.2ppm. Compare that to how steep the slope is from 0.5ppm to undetectable for all the other bacteria...

It really looks like while other bacteria sources chomp through the last bit of detectable ammonia, Fritz really stops bothering to do much with ammonia once the amount drops to < 0.5ppm. This means that there is plenty of ammonia that would be left for uglies to consume. You can imagine a robust economy of <0.1ppm total ammonia levels being produced and consumed without having to fight the Fritz bacteria for it.

(Fritz defenders that are so inclined are welcome to flip the argument around and talk about how this product is ideal for coral nutrition because of the exact same thing. It isn't going to bother with 0.0X ppm of ammonia - or nitrite - and leave those for hungry corals)

Aside from Fritz there are a number of bacterial products that oxidize ammonia just fine but seem to have no nitrite oxidizers in the mix at all. Zero NO2 consumption for weeks.
Like MB Start XLM. I think NO2 is slightly yummier than NO3 for photosynthetic stuff, and so all other things being equal, bacterial products that leave NO2 untouched might allow more uglies than those that convert the NO2->NO3 super aggressively (biospira accumulates such tiny amounts of NO2 ever).

To go way out in left field where I have no data - One and Only was cultured up and sequenced in a paper and they found that it showed up as having a lot of Archaea.
If true, it's fascinating to me. It could explain very slow growth rates under conditions where other products grew faster. More interesting - reasoning from published papers, we believe that archaea have higher affinity for eating tiny microdoses of ammonia, thus after the agonizingly slow cycling process, maybe the O&O microbes are actually a really strong competitor for tiny doses of ammonia and might be good at preventing nuisance growth? (no idea if any of that is true, but it makes me wonder if I could actually see differences post-cycling in how quickly these communities would eat say 0.02ppm ammonia.)

 

[Randy Holmes-Farley]

It really looks like while other bacteria sources chomp through the last bit of detectable ammonia, Fritz really stops bothering to do much with ammonia once the amount drops to < 0.5ppm. This means that there is plenty of ammonia that would be left for uglies to consume. You can imagine a robust economy of <0.1ppm total ammonia levels being produced and consumed without having to fight the Fritz bacteria for it.

I'm confused. Are we looking at the upper left graph? It hits very low levels faster than anything else shown in that post?

 

[taricha]

I'm confused. Are we looking at the upper left graph? It hits very low levels faster than anything else shown in that post?

Right, it's undisputed that Fritz eats the high levels of ammonia very fast.
but look at the rate of consumption once the ammonia gets below 0.5ppm.... circled in green.
Group 3

Group2

Group1

If you compare the slopes at these low ammonia values, Fritz is uniquely flat here, after being much faster at higher levels, suggesting that when the ammonia drops below a couple of tenths ppm, it doesn't really do much. The other bacteria tested all went straight to zero once they got the ammonia that low.

 

[brandon429]

@taricha

please let me know how you are discerning this measure/accuracy/gradient using api=

Fritz really stops bothering to do much with ammonia once the amount drops to < 0.5ppm


what if there's action in between .5 ppm and .005 that isn't being measured?


how can a color gradient be turned into a tenths ppm level reading for that graph using api, that's a really precise level...I'm amazed we don't require that to be readout on a digital meter for this degree of charting

what would be the level for a mainly yellow color, but the slightest detectable green hue? in between the two lowest comparison options off the card, we'd estimate the middle level and assign a reading such as .35 ppm?

any reader is going to see those charts as the absolute final say in the matter, it honestly seems like a large fill in is being made for chunks of data we can't verify or see

 

[Randy Holmes-Farley]

Right, it's undisputed that Fritz eats the high levels of ammonia very fast.
but look at the rate of consumption once the ammonia gets below 0.5ppm.... circled in green.
Group 3

Group2

Group1

If you compare the slopes at these low ammonia values, Fritz is uniquely flat here, after being much faster at higher levels, suggesting that when the ammonia drops below a couple of tenths ppm, it doesn't really do much. The other bacteria tested all went straight to zero once they got the ammonia that low.

I agree the slope is leveling off, but it still hits any low level you want before anything else does. It does not look flat to me, it looks quite typical of a chemical rection:

First order, zero order and non-linear elimination kinetics

First order elimination kinetics is where a constant proportion (eg. a percentage) of drug is eliminated per unit time, whereas zero order elimination kinetics is where a constant amount (eg. so many milligrams) of drug is eliminated per unit time. First order kinetics is a...

derangedphysiology.com

 

[brandon429]

@Dr. Reef

hey friend

would you please consider mailing taricha a seneye to use here for back checks on the data I would 100% trust him to mail it back when done. what he will do with the device will impact cycling bigtime. taricha with a calibrated seneye (run the slide on a cycled reef tank/note the baseline then use for cycling charts) will change cycling science at a fast rate.

 

[taricha]

@taricha

please let me know how you are discerning this measure/accuracy/gradient using api=

Fritz really stops bothering to do much with ammonia once the amount drops to < 0.5ppm


what if there's action in between .5 ppm and .005 that isn't being measured?


how can a color gradient be turned into a tenths ppm level reading for that graph using api, that's a really precise level...I'm amazed we don't require that to be readout on a digital meter for this degree of charting

Sure. I can go through more details, but it's quite digital, I can assure you.
So I mix up a calibration curve for zero, 0.5, 1.0, 1.5, 2.0ppm etc or whatever.
react the samples in tiny cuvettes, shoot them with the spectrometer, and get something like this..... (two values were me checking the stability at 33 and 49 minutes)

I then plot the absorbance at that peak vs the stock ammonia concentration to get a curve like this.....

Here's API total ammonia test

Tightly linear over the range [0 - 2ppm].

Then I use that regression equation for this recipe. With each day's set of measurements I run a zero ammonia tank water side-by-side to check the zero. So any particular day I'm measuring these guys on the spectrometer....

the spectrometer of the above ammonia test cuvettes gives me this.....

And then I put the digital absorbance values from the spectrometer into a spreadsheet to calculate the concentrations of ammonia and whatever else. So that's how it goes. The zero might be off by +-0.02ppm either way, but anything much more than that is pretty easy to track.

would you please consider mailing taricha a seneye to use here for back checks on the data I would 100% trust him to mail it back when done. what he will do with the device will impact cycling bigtime. taricha with a calibrated seneye (run the slide on a cycled reef tank/note the baseline then use for cycling charts) will change cycling science at a fast rate.

Honestly, A seneye wouldn't help me. A seneye would easily measure 1 sample 10 or 20 times a day if I wanted. But I am not measuring one sample. I'm measuring like 10 samples every 1-3 days.

 

[taricha]

I agree the slope is leveling off, but it still hits any low level you want before anything else does. It does not look flat to me, it looks quite typical of a chemical rection:

in theory, the others are also following a similar 1st order reaction kinetic and slowing down very very close to zero. They just do it at such a low level I can't see the slow-down. Fritz does it at a couple of tenths ppm.

And yes, I guess what I'm actually suggesting is that the next 0.1ppm ammonia that got excreted into that sample would be eaten faster by others than by Fritz, based on the ammonia slopes of those samples down at low tenths of a ppm. But I didn't actually add that next 0.1ppm so I'm gesturing at something imaginary, I suppose.

 

[brandon429]

none of your samples hit thousandths ppm at any time? after any wait duration or did some values reach that average?

 

[taricha]

none of your samples hit thousandths ppm at any time? after any wait duration or did some values reach that average?

I'm work in total ammonia since that's what's measured, but with the pH measurements I can calculate NH3 and get the thousandths like seneye.

at 7.8 pH 0.20 ppm total ammonia ( at 75F) = 0.0053 ppm NH3 etc.

 

[Dan_P]

On the one hand, I have no uglies+nitrifier-growth-experiments that would give me any direct basis to answer this. But let me make up a very speculative response based on some data in this thread anyway...

If I wanted to cycle a tank with ammonia oxidizers and still grow a bunch of uglies, I'd pick Fritz. Here's why: the curve shape for Fritz against ammonia concentration is unique - it's extremely flat at low concentrations of ammonia.....

Note how Fritz really drops to a crawl at low amounts of ammonia <0.2ppm. Compare that to how steep the slope is from 0.5ppm to undetectable for all the other bacteria...

It really looks like while other bacteria sources chomp through the last bit of detectable ammonia, Fritz really stops bothering to do much with ammonia once the amount drops to < 0.5ppm. This means that there is plenty of ammonia that would be left for uglies to consume. You can imagine a robust economy of <0.1ppm total ammonia levels being produced and consumed without having to fight the Fritz bacteria for it.

(Fritz defenders that are so inclined are welcome to flip the argument around and talk about how this product is ideal for coral nutrition because of the exact same thing. It isn't going to bother with 0.0X ppm of ammonia - or nitrite - and leave those for hungry corals)

Aside from Fritz there are a number of bacterial products that oxidize ammonia just fine but seem to have no nitrite oxidizers in the mix at all. Zero NO2 consumption for weeks.
Like MB Start XLM. I think NO2 is slightly yummier than NO3 for photosynthetic stuff, and so all other things being equal, bacterial products that leave NO2 untouched might allow more uglies than those that convert the NO2->NO3 super aggressively (biospira accumulates such tiny amounts of NO2 ever).

To go way out in left field where I have no data - One and Only was cultured up and sequenced in a paper and they found that it showed up as having a lot of Archaea.
If true, it's fascinating to me. It could explain very slow growth rates under conditions where other products grew faster. More interesting - reasoning from published papers, we believe that archaea have higher affinity for eating tiny microdoses of ammonia, thus after the agonizingly slow cycling process, maybe the O&O microbes are actually a really strong competitor for tiny doses of ammonia and might be good at preventing nuisance growth? (no idea if any of that is true, but it makes me wonder if I could actually see differences post-cycling in how quickly these communities would eat say 0.02ppm ammonia.)

Wouldn’t it be funny if cycling an aquarium encouraged benthic algae blooms in new aquaria. Maybe biodiversity isn’t as important as having a low concentration of nitrifying bacteria in a new aquarium.

 

[taricha]

And here's the data for Group 4: Saltwater, Fritz Turbo, One & Only (bottle 2), StartSmart, Fluval Cycle, Petco "Live Rock"
(details on the types tested here in post 164)


Group 4 Ammonia and Nitrite measurements

All tested bacteria in this group processed away ammonia in the 30 days measured, except for the negative control of a drop of saltwater from my tank, which did nothing as in earlier rounds.

On NO2, the samples had less success, with the petco "live rock" (fast) and the Fritz turbo (slower) being the only samples that clearly delivered nitrite oxidizers. One replicate of Smart Start processed nitrite very late, but the other replicate did nothing - suggesting contamination on my part rather than the NO2 oxidizers actually being a major component of that bottled product.

Group 4 Nitrate and pH data

The Nitrate data confirms that, as expected, the samples that processed away nitrite, did so according to theory, and essentially all the processed ammonia ended up as measurable NO3. So without light or food, classic nitrification: (ammonia->NO2->NO3) is again the only viable pathway in these samples.

The pH data is a mess, and serves only as a fuzzy confirmation of the timeline of when each bacterial sample did the majority of ammonia oxidation. Fritz in the fist 8 days, Smart start day 4-12, Fluval cycle and One and Only in the 3rd and 4th weeks. It also says that the Petco Live Rock is a mess for reasons I'll discuss below.

Commentary
Considering this group included stuff that I had a lot of skepticism about, that all oxidized Ammonia could be considered a mild surprise.
Fritz (positive control) was fast starting as before, then the SmartStart product that I'd never heard of but my LFS is full of, was also active near immediately. The next fastest responder (and actually the first to get ammonia to zero) was the worst-looking painted concrete Petco "Live rock" chunk I could find.
Fluval cycle also responded eventually, and bringing up the rear was the new bottle of One and Only, which became measurably active around day 20, and cleared ammonia by day 30. It was a bit faster than my first bottle of O&O in group 2, but really not too much different. (There are other possible explanations about why these conditions might be responsible for the slow response of my O&O results, but "dud bottle" isn't one of them. At this point, clear evidence of rapid ammonia oxidation from One and Only isn't something I've seen under any other conditions either.)

On Nitrite, this group struggled. Aside from the Petco live rock (fast) and Fritz (slow), none of the others seemed to do anything persuasive to NO2 in 35 days. It is fortunate that we don't care about Nitrite in saltwater, because it seems a number of products have no effect on NO2 in a reasonable ( <30 day) time frame.

On the Petco "Live Rock" I intentionally selected the lowest quality material I could find. It looked like white ceramic with pink & purple spray paint. When I broke off chunks to put in the sample bottles, apparently the insides were not even fully cured.
I thought those samples were toast at the first check, the pH was ~8.5 due to the uncured broken surface of concrete-like stuff continuing to react with the CO2 in the sample. Before giving up, I gave it another shot by breathing into the bottle airspace to add CO2 and get the pH back down to low 8's and both the ammonia and nitrite oxidizing bacteria were rapidly active in these samples. This seems to point to the validity of the notion "For cycling, just get something from a live system" - at least in regards to nitrifiers, it seems true that the surface needs not be of any high quality - just surface in contact with tank water containing live animals. Don't extend that argument to the enormous diversity of bacteria on/in porous material, but for cycling bacteria - any surface will probably do. @Dan_P grows fine nitrifying biofilms on glass slides.

 

[Dan_P]

And here's the data for Group 4: Saltwater, Fritz Turbo, One & Only (bottle 2), StartSmart, Fluval Cycle, Petco "Live Rock"
(details on the types tested here in post 164)


Group 4 Ammonia and Nitrite measurements

All tested bacteria in this group processed away ammonia in the 30 days measured, except for the negative control of a drop of saltwater from my tank, which did nothing as in earlier rounds.

On NO2, the samples had less success, with the petco "live rock" (fast) and the Fritz turbo (slower) being the only samples that clearly delivered nitrite oxidizers. One replicate of Smart Start processed nitrite very late, but the other replicate did nothing - suggesting contamination on my part rather than the NO2 oxidizers actually being a major component of that bottled product.

Group 4 Nitrate and pH data

The Nitrate data confirms that, as expected, the samples that processed away nitrite, did so according to theory, and essentially all the processed ammonia ended up as measurable NO3. So without light or food, classic nitrification: (ammonia->NO2->NO3) is again the only viable pathway in these samples.

The pH data is a mess, and serves only as a fuzzy confirmation of the timeline of when each bacterial sample did the majority of ammonia oxidation. Fritz in the fist 8 days, Smart start day 4-12, Fluval cycle and One and Only in the 3rd and 4th weeks. It also says that the Petco Live Rock is a mess for reasons I'll discuss below.

Commentary
Considering this group included stuff that I had a lot of skepticism about, that all oxidized Ammonia could be considered a mild surprise.
Fritz (positive control) was fast starting as before, then the SmartStart product that I'd never heard of but my LFS is full of, was also active near immediately. The next fastest responder (and actually the first to get ammonia to zero) was the worst-looking painted concrete Petco "Live rock" chunk I could find.
Fluval cycle also responded eventually, and bringing up the rear was the new bottle of One and Only, which became measurably active around day 20, and cleared ammonia by day 30. It was a bit faster than my first bottle of O&O in group 2, but really not too much different. (There are other possible explanations about why these conditions might be responsible for the slow response of my O&O results, but "dud bottle" isn't one of them. At this point, clear evidence of rapid ammonia oxidation from One and Only isn't something I've seen under any other conditions either.)

On Nitrite, this group struggled. Aside from the Petco live rock (fast) and Fritz (slow), none of the others seemed to do anything persuasive to NO2 in 35 days. It is fortunate that we don't care about Nitrite in saltwater, because it seems a number of products have no effect on NO2 in a reasonable ( <30 day) time frame.

On the Petco "Live Rock" I intentionally selected the lowest quality material I could find. It looked like white ceramic with pink & purple spray paint. When I broke off chunks to put in the sample bottles, apparently the insides were not even fully cured.
I thought those samples were toast at the first check, the pH was ~8.5 due to the uncured broken surface of concrete-like stuff continuing to react with the CO2 in the sample. Before giving up, I gave it another shot by breathing into the bottle airspace to add CO2 and get the pH back down to low 8's and both the ammonia and nitrite oxidizing bacteria were rapidly active in these samples. This seems to point to the validity of the notion "For cycling, just get something from a live system" - at least in regards to nitrifiers, it seems true that the surface needs not be of any high quality - just surface in contact with tank water containing live animals. Don't extend that argument to the enormous diversity of bacteria on/in porous material, but for cycling bacteria - any surface will probably do. @Dan_P grows fine nitrifying biofilms on glass slides.

Why the ammonia consumption differences? Species differences in products? Initial number of bacteria differences?

 

[taricha]

Why the ammonia consumption differences? Species differences in products? Initial number of bacteria differences?

some differences can be attributed to the size of the initial delivered bacterial population, but not all the differences.
If you see two products where you can just time shift one curve from product A and delay it for a few days and it nicely overlaps the exact curve shape of another product B, then that's one where you can say it's consistent with the notion that once B scaled up to the initial functional population of A, they acted the same. Fluval cycle looks the same as SmartStart but 10 days behind. So it looks like on day 12, fluval cycle had a community that acted like Smart Start on day 2, and each day after they were indistinguishable.

But others don't map cleanly onto each other with time shifts, they have very different ammonia response curves. The Petco rock was the fastest of anything tested from day 10-12, but did nothing for the first 7 days. So clearly a different response pattern. Fritz again shows that it is the fastest on the day you challenge it with big ammonia dose, and gets very clearly slower every day after as the concentration goes lower.
You can't just account for those rate changes with initial population size alone: the bacteria have to behave differently in growth rate, activation time to stimuli, concentration preference etc. Strongly suggests there's some species differences in there too.

 

[Dan_P]

some differences can be attributed to the size of the initial delivered bacterial population, but not all the differences.
If you see two products where you can just time shift one curve from product A and delay it for a few days and it nicely overlaps the exact curve shape of another product B, then that's one where you can say it's consistent with the notion that once B scaled up to the initial functional population of A, they acted the same. Fluval cycle looks the same as SmartStart but 10 days behind. So it looks like on day 12, fluval cycle had a community that acted like Smart Start on day 2, and each day after they were indistinguishable.

But others don't map cleanly onto each other with time shifts, they have very different ammonia response curves. The Petco rock was the fastest of anything tested from day 10-12, but did nothing for the first 7 days. So clearly a different response pattern. Fritz again shows that it is the fastest on the day you challenge it with big ammonia dose, and gets very clearly slower every day after as the concentration goes lower.
You can't just account for those rate changes with initial population size alone: the bacteria have to behave differently in growth rate, activation time to stimuli, concentration preference etc. Strongly suggests there's some species differences in there too.

Thanks. These are very useful observations to consider when designing experiments to study the possibility of AOB enabling the uglies.