At what point does glutaradehyde become toxic for beneficial bacteria in an aquarium?

Matt F.

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I've been using glutaraldehyde to inhibit algae growth in my 55 gallon tank...as far as I can tell it has done a good job.

I have recently read a journal article that was linked by Tom in one of the threads here on TBR on the topic of glutaradehyde toxicity.

Specifically I'm interested in the long term effects on fish and shrimp (Amanos). I am also interested in the effect of glutaradehyde on beneficial bacteria in the aquarium since it is used as a antiseptic/biocide.

http://www.glerl.noaa.gov/pubs/fulltext/2005/20050003.pdf

Here is my regime:

Water change day: 5ml per 10 gallons (25 ml)
Every day thereafter: 10 ml per 55 gallons (double Seachem's recommended non-water change day dose).

Can I safely reduce/limit the dosage to just water change days once a week without an increase in GSA and GDA growth?

What are your thoughts?

Tom how/when and what dosage do you recommend?
 
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Biollante

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Not Tom Barr...

Hi Matt,

{Not Tom Barr so this is probably wrong. I wrote this prior to realizing the question was for Tom Barr, pardon my post.}

I think glutaraldehyde toxicity starts as low as 1-ppm (I think based on 96 hour exposure).

What you want to know may be in the document you referenced.

Correct water problems to avoid significant GSA and GDA problems.

Using potent disinfectants off label is not a great idea, especially long term.

Biollante
 

Matt F.

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Biollante-

I appreciate your response. No need for pardon. I'm just glad I have an answer that makes sense.

As of yesterday I stopped dosing excel. The shrimp and fish seem more lively (could be psychological...lol).

I don't want to cause discomfort for my inverts, so that is partially the reason I stopped dosing. I have, however, increased co2 till my drop checker w/ 4dkh is lime green. I'm getting tons of pearling after a couple hours.

I also dose EI, so I'm hoping phosphate (GSA) is okay.
I'm okay with a little algae as a trade off for healthier tank inhabitants (not that they are unhealthy).
I'm going to cease dosing excel for a while.

Thanks.
 

Matt F.

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I think I have answered my own question:

I've been dosing 200% the recommended dose daily (10 ml) and no deaths (fish, shrimp, nerites). The rcs and amanos are berried and active. The nerite does laps in the tank.

Excel at this level (200% the recommended daily non-water change-day dose) is fine.

I also do the recommmended water change day dose of (25ml per 50 gallons).