For years, many aquarists and I religiously dose our tanks with Prodibio BioDigest, in reliance of the claims the product, through a "community" of "bacteria in optimal proportion" would help with "a quick set up of the biological filtration" and with the nitrifying and denitrifying process in general.
My recent research on the product makes me doubt all these claims. Through this thread, I invite R2R members and Prodibio to examine the results and join the discussion. I truly hope we can demonstrate some level of usefulness on the product, instead of continuing to dose it without knowing what's really going on.
1. 16S rRND Sequencing on Prodibio BioDigest
I have 16S rRNA sequencing results of BioDigest on hand. I am not entirely sure whether I could get into trouble for publishing them, given that Prodibio website explicitly says that their bacterial composition is "confidential." I am also withholding the results for now out of courtesy to Prodibio.
But what I can say is that BioDigest does not appear to contain any nitrifying bacteria in the strict sense. In other words, it does not contain any autotrophic bacteria at all, not to mention strain from the Nitrobacteraceae family. This is consistent with the findings of @Dr. Reef study on Bottled Bacteria, where Prodibio could not reduce ammonia level without organic carbon help.
So BioDigest wasn't really "helping with a quick set up of biological filtration" in ways that reasonable consumers who read this claim would have hoped. It appears that Prodibio was aiming to be technically correct but misleading, hoping that no one would bother to dig deeper.
2. Prodibio BioDigest Likely Doesn't Help with Ammonia Oxidation
One would have hoped that, even if BioDigest does not contain true nitrifying bacteria, at least its heterotrophic strains could still consume ammonia when rapidly multiplies.
Well, it didn't.
I tested 3 times with the following setup:
1 gallon of fresh seawater in a nano tank with no filter media.
Heavy aeration
1 ml of TM All-for-Reed was added for trace minerals.
Phosphate was adjusted to 0.1 ppm with KH2PO4.
Ammonia was adjusted to 1.0 ppm (NH3-N) with NH3CL.
0.1g, 0.5g, and 1.0g of brown sugar was added in the first, second, and third run, respectively
Prodibio BioDigest did not bring down ammonia in any of the three runs within 48 hours. Nor did BioDigest beat the control tank in any of the run. In the second run after 72 hours, both the control tank and the BioDigest tank became cloudy, with ammonia starting to drop. This suggests that external heterotrophic bacteria started to multiply and brought ammonia down. I suspect this is what happened in @Dr. Reef study. When he added fish food and witnessed ammonia starting to drop in the BioDigest tank, it was probably some naturally occurring Bacillus strains that were already in the tank water doing the job.
3. Prodibio BioDigest Likely Doesn't Help with Nitrate Reduction
Determined to find at least one concrete case where BioDigest could help, I turned to the claim that it reduces "nitrates and phosphates." The 16s rRNA results do support this claim as there is a Pseudomonas strain known to be an aerobic denitrifican present in the vial in high concentration.
Except that it didn't work.
I again tested 3 times with the following setup:
1 gallon of changed out seawater from refugium.
Heavy aeration
1 ml of TM All-for-Reed was added for trace minerals.
Phosphate was adjusted to 0.1 ppm with KH2PO4.
Nitrates tested to be about 10 ppm (NO3-N).
0.1g, 0.5g, and 1.0g of brown sugar was added in the first, second, and third run, respectively.
Again, with 48 hours on each run, nitrates never went down. Nor did phosphate.
4. What's Next
Could someone, including Prodibio, provide one scenario (that'd actually happen in home aquaria) where BioDigest can demonstrably help with, well, anything? Please also do not require the use of Biotim, as it introduces yet another black box shrouded in mystery.
I would very much like to measure an improvement in any major water parameter that can be convincingly attributed to BioDigest. That would be a much better ending to this story than accepting that I and many others have been paying for an expensive placebo all these years.
Thanks.
McGullen
My recent research on the product makes me doubt all these claims. Through this thread, I invite R2R members and Prodibio to examine the results and join the discussion. I truly hope we can demonstrate some level of usefulness on the product, instead of continuing to dose it without knowing what's really going on.
1. 16S rRND Sequencing on Prodibio BioDigest
I have 16S rRNA sequencing results of BioDigest on hand. I am not entirely sure whether I could get into trouble for publishing them, given that Prodibio website explicitly says that their bacterial composition is "confidential." I am also withholding the results for now out of courtesy to Prodibio.
But what I can say is that BioDigest does not appear to contain any nitrifying bacteria in the strict sense. In other words, it does not contain any autotrophic bacteria at all, not to mention strain from the Nitrobacteraceae family. This is consistent with the findings of @Dr. Reef study on Bottled Bacteria, where Prodibio could not reduce ammonia level without organic carbon help.
So BioDigest wasn't really "helping with a quick set up of biological filtration" in ways that reasonable consumers who read this claim would have hoped. It appears that Prodibio was aiming to be technically correct but misleading, hoping that no one would bother to dig deeper.
2. Prodibio BioDigest Likely Doesn't Help with Ammonia Oxidation
One would have hoped that, even if BioDigest does not contain true nitrifying bacteria, at least its heterotrophic strains could still consume ammonia when rapidly multiplies.
Well, it didn't.
I tested 3 times with the following setup:
1 gallon of fresh seawater in a nano tank with no filter media.
Heavy aeration
1 ml of TM All-for-Reed was added for trace minerals.
Phosphate was adjusted to 0.1 ppm with KH2PO4.
Ammonia was adjusted to 1.0 ppm (NH3-N) with NH3CL.
0.1g, 0.5g, and 1.0g of brown sugar was added in the first, second, and third run, respectively
Prodibio BioDigest did not bring down ammonia in any of the three runs within 48 hours. Nor did BioDigest beat the control tank in any of the run. In the second run after 72 hours, both the control tank and the BioDigest tank became cloudy, with ammonia starting to drop. This suggests that external heterotrophic bacteria started to multiply and brought ammonia down. I suspect this is what happened in @Dr. Reef study. When he added fish food and witnessed ammonia starting to drop in the BioDigest tank, it was probably some naturally occurring Bacillus strains that were already in the tank water doing the job.
3. Prodibio BioDigest Likely Doesn't Help with Nitrate Reduction
Determined to find at least one concrete case where BioDigest could help, I turned to the claim that it reduces "nitrates and phosphates." The 16s rRNA results do support this claim as there is a Pseudomonas strain known to be an aerobic denitrifican present in the vial in high concentration.
Except that it didn't work.
I again tested 3 times with the following setup:
1 gallon of changed out seawater from refugium.
Heavy aeration
1 ml of TM All-for-Reed was added for trace minerals.
Phosphate was adjusted to 0.1 ppm with KH2PO4.
Nitrates tested to be about 10 ppm (NO3-N).
0.1g, 0.5g, and 1.0g of brown sugar was added in the first, second, and third run, respectively.
Again, with 48 hours on each run, nitrates never went down. Nor did phosphate.
4. What's Next
Could someone, including Prodibio, provide one scenario (that'd actually happen in home aquaria) where BioDigest can demonstrably help with, well, anything? Please also do not require the use of Biotim, as it introduces yet another black box shrouded in mystery.
I would very much like to measure an improvement in any major water parameter that can be convincingly attributed to BioDigest. That would be a much better ending to this story than accepting that I and many others have been paying for an expensive placebo all these years.
Thanks.
McGullen
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