QT and Biofilm

[jwshiver]

I've had my QT running for several months. When I treat my QT with Prazi my water turns very cloudy for days on end. Sounds like I need to break it down:mad:

 

[Brew12]

I've had my QT running for several months. When I treat my QT with Prazi my water turns very cloudy for days on end. Sounds like I need to break it down:mad:

It does sound that way.

 

[Crashjack]

Has anybody tried disinfecting with potassium/sodium metabisulphite? This is used in winemaking (my experience with it as a home wine maker). It rinses very easily (a lot easier than bleach) and is very effective and easy to use.

Also, might alternating treatment methods slow the biofilm process? For instance, treating a fish with CP and then treating the next fish with copper? This would cut the bacteria's food source and exposure to that food source in half, and the copper might help to beat the biofilm down before CP is used again. This doesn't address Prazi but might help with CP.

 

[Humblefish]

Also, might alternating treatment methods slow the biofilm process? For instance, treating a fish with CP and then treating the next fish with copper? This would cut the bacteria's food source and exposure to that food source in half, and the copper might help to beat the biofilm down before CP is used again. This doesn't address Prazi but might help with CP.

Heterotrophs also use organic carbon as food, so just eliminating CP from the water isn't going to slow their propagation much. Dosing chlorine (10ppm) in-between QT batches will kill most of the bacteria and should fully evaporate in 1 weeks time; but once they form a biofilm chlorine may no longer be as effective. I think breaking your entire QT down and sanitizing everything (with vinegar) is the only way to ensure that the (non-copper) meds you are dosing are staying active in the water. A breakdown every 2-3 months might be good enough if you are dosing chlorine on a regular basis to keep bacteria levels knocked back.

 

[Crashjack]

Heterotrophs also use organic carbon as food, so just eliminating CP from the water isn't going to slow their propagation much. Dosing chlorine (10ppm) in-between QT batches will kill most of the bacteria and should fully evaporate in 1 weeks time; but once they form a biofilm chlorine may no longer be as effective. I think breaking your entire QT down and sanitizing everything (with vinegar) is the only way to ensure that the (non-copper) meds you are dosing are staying active in the water. A breakdown every 2-3 months might be good enough if you are dosing chlorine on a regular basis to keep bacteria levels knocked back.

So are you saying that the biofilm grows as a result of the tank in general (e.g. exists and grows in all tanks, medicated or not)?

 

[Humblefish]

So are you saying that the biofilm grows as a result of the tank in general (e.g. exists and grows in all tanks, medicated or not)?

Basically, yes. In time, bacteria will stick to each other and then adhere to a surface. Thus forming a biofilm.

This starts happening within a few months time, whether it be a DT or QT. It explains why most meds (except for copper) are basically ineffective in a DT. Prazipro would be another exception, since it only needs around 1 hour to do it's job, and I doubt it can be biodegraded that quickly.

 

[Crashjack]

Basically, yes. In time, bacteria will stick to each other and then adhere to a surface. Thus forming a biofilm.

This starts happening within a few months time, whether it be a DT or QT. It explains why most meds (except for copper) are basically ineffective in a DT. Prazipro would be another exception, since it only needs around 1 hour to do it's job, and I doubt it can be biodegraded that quickly.

Would this typically be hard surfaces? In other words, could I swap out containers (I have 2 Sterillite containers) and sanitize my PVC elbows, but keep my sponge filter running? I remember having the same issue 20 years ago with seeding sponge filters in that they never want to grow enough bacteria during seeding to support a QT. My guess is that they would seed a lot "fuller" if they were seeded in a heavy-loaded, well established display tank. My display is neither.

 

[Brew12]

So are you saying that the biofilm grows as a result of the tank in general (e.g. exists and grows in all tanks, medicated or not)?

Basically, yes. In time, bacteria will stick to each other and then adhere to a surface. Thus forming a biofilm.

This starts happening within a few months time, whether it be a DT or QT. It explains why most meds (except for copper) are basically ineffective in a DT. Prazipro would be another exception, since it only needs around 1 hour to do it's job, and I doubt it can be biodegraded that quickly.

All tanks will grow biofilms yet not all biofilms will break down medications (or any other chemical) at the same rate. The bacteria that comprise the biofilm in our systems is diverse and surprisingly specialized. A tank never having been exposed to CP will break it down slower than one that has.

We even see this with nitrifying bacteria. If you take a new tank and immediately dose it to 8ppm ammonia and always keep it above 5ppm the bacteria that dominate will be ones that function best at those levels. Once ammonia drops below 2ppm the bacteria you established will be much less effective at breaking it down and you will likely see your cycle "stall" at 0.5ppm ammonia as bacteria that more effectively consume ammonia at that concentration start to dominate. This works backwards, too. If you take a bottle of BioSpira and dump it in a tank with 0.25ppm ammonia you will most likely see instant results and oppm ammonia. If you dump it in a tank with 5ppm ammonia it will not work well at all.

 

[Humblefish]

Would this typically be hard surfaces? In other words, could I swap out containers (I have 2 Sterillite containers) and sanitize my PVC elbows, but keep my sponge filter running? I remember having the same issue 20 years ago with seeding sponge filters in that they never want to grow enough bacteria during seeding to support a QT. My guess is that they would seed a lot "fuller" if they were seeded in a heavy-loaded, well established display tank. My display is neither.

In my last DT, I was able to seed dry sponges in roughly 30 days. I would keep multiple sponges going down in the sump at all times. However, it was a heavy-loaded, well established tank.

An alternative is to use a bacteria in a bottle product to seed your sponge instead: https://www.reef2reef.com/threads/ammonia-control-in-a-hospital-tank.296119/

 

[Crashjack]

In my last DT, I was able to seed dry sponges in roughly 30 days. I would keep multiple sponges going down in the sump at all times. However, it was a heavy-loaded, well established tank.

An alternative is to use a bacteria in a bottle product to seed your sponge instead: https://www.reef2reef.com/threads/ammonia-control-in-a-hospital-tank.296119/

Good stuff! I read that thread a couple of months ago but forgot about it. For some reason, I was thinking you shouldn't use bacteria in a bottle with medication for reasons other than the medication potentially slowing the bacteria growth. I'll try Biospira or another product with my next sponge filter.

 

[Crashjack]

All tanks will grow biofilms yet not all biofilms will break down medications (or any other chemical) at the same rate. The bacteria that comprise the biofilm in our systems is diverse and surprisingly specialized. A tank never having been exposed to CP will break it down slower than one that has.

We even see this with nitrifying bacteria. If you take a new tank and immediately dose it to 8ppm ammonia and always keep it above 5ppm the bacteria that dominate will be ones that function best at those levels. Once ammonia drops below 2ppm the bacteria you established will be much less effective at breaking it down and you will likely see your cycle "stall" at 0.5ppm ammonia as bacteria that more effectively consume ammonia at that concentration start to dominate. This works backwards, too. If you take a bottle of BioSpira and dump it in a tank with 0.25ppm ammonia you will most likely see instant results and oppm ammonia. If you dump it in a tank with 5ppm ammonia it will not work well at all.

Great info. Thanks!

 

[Crashjack]

A couple more questions:

1. Since time is an issue with biofilms, wouldn't bacteria in a bottle be preferred over seeding a filter in an established tank? In other words, wouldn't exposing your bio filter to an established tank increase the likelihood of introducing an established, undesirable biofilm to your QT?
2. (A little off-topic), if using a plastic container like a Sterilite container, would it be better to always use one container for CP and one for copper when swapping them out, just in case there is any leaching?

 

[Brew12]

A couple more questions:

1. Since time is an issue with biofilms, wouldn't bacteria in a bottle be preferred over seeding a filter in an established tank? In other words, wouldn't exposing your bio filter to an established tank increase the likelihood of introducing an established, undesirable biofilm to your QT?
2. (A little off-topic), if using a plastic container like a Sterilite container, would it be better to always use one container for CP and one for copper when swapping them out, just in case there is any leaching?

Unless you have used a medication like Prazipro in your DT a few times I wouldn't be concerned about using a sponge seeded in it.

For the container question, I have no idea.

 

[Humblefish]

Since time is an issue with biofilms, wouldn't bacteria in a bottle be preferred over seeding a filter in an established tank? In other words, wouldn't exposing your bio filter to an established tank increase the likelihood of introducing an established, undesirable biofilm to your QT?

Like Brew said, I wouldn't be concerned about using a seeded sponge. This is more of a time sensitive issue; meaning you've got about 2-3 months before bacteria starts inundating your QT to the point where you really need to just break it down & start over. Using a seeded sponge will be the "spark" to allow bacteria to start spreading throughout the QT again, but once more it will take 2-3 months before biodegradation becomes an issue.

(A little off-topic), if using a plastic container like a Sterilite container, would it be better to always use one container for CP and one for copper when swapping them out, just in case there is any leaching?

I've tested this with copper in a Sterilite, and a public aquarium I advise has done the same with CP (using a spectrophotometer). Absorption was minimal in both cases.

 

[jasonrusso]

If you leave the QT "fallow" with carbon to remove the meds, wouldn't the bacteria that feeds on the medications die off eventually?

I can see if the fuel is constantly being added the bacteria will continue to multiply.

 

[Humblefish]

If you leave the QT "fallow" with carbon to remove the meds, wouldn't the bacteria that feeds on the medications die off eventually?

I can see if the fuel is constantly being added the bacteria will continue to multiply.

Bacteria can live a long time without nourishment; although in an aquarium there will almost always be waste, organics and dead organisms for bacteria to decompose.

If you could somehow eliminate all/most bacteria from your DT (i.e. chlorine), you would in effect have an uncycled tank.

 

[jasonrusso]

Bacteria can live a long time without nourishment; although in an aquarium there will almost always be waste, organics and dead organisms for bacteria to decompose.

If you could somehow eliminate all/most bacteria from your DT (i.e. chlorine), you would in effect have an uncycled tank.

So am I incorrect in thinking that a particular bacteria only performs one function?

Basically bacteria strain "A" converts ammonia to nitrite. Strain "B" converts nitrite to nitrate, "C" consumes prazi, etc.

If that was/is the case, wouldn't the strain "c" die off eventually?

 

[Humblefish]

So am I incorrect in thinking that a particular bacteria only performs one function?

Basically bacteria strain "A" converts ammonia to nitrite. Strain "B" converts nitrite to nitrate, "C" consumes prazi, etc.

If that was/is the case, wouldn't the strain "c" die off eventually?

I'm saying that bacteria are complex and usually consume more than just one food source. There's no one particular strain which feeds exclusively on specific medications or even medications in general. For example, if a particular strain were responsible for degrading all of the praziquantel in the water, they are not going to just starve to death once all the prazi is gone. Those bacteria subsisted on something else before prazi came along, and the colony as a whole will adapt & survive once the prazi is gone.

Now, the presence of prazi may have fueled their growth and their numbers may reduce after it is gone. OR it may have just been a snack and they have plenty of their main food source left in the aquarium.

 

[Crashjack]

Unless you have used a medication like Prazipro in your DT a few times I wouldn't be concerned about using a sponge seeded in it.

For the container question, I have no idea.

Like Brew said, I wouldn't be concerned about using a seeded sponge. This is more of a time sensitive issue; meaning you've got about 2-3 months before bacteria starts inundating your QT to the point where you really need to just break it down & start over. Using a seeded sponge will be the "spark" to allow bacteria to start spreading throughout the QT again, but once more it will take 2-3 months before biodegradation becomes an issue.

I've tested this with copper in a Sterilite, and a public aquarium I advise has done the same with CP (using a spectrophotometer). Absorption was minimal in both cases.

Thanks guys! My worry with leaching was in regards to say wrasses, which are sensitive to CP, being quarantined in a container that contained CP a week or two ago... sounds like no worries as long as the CP was removed.

 

[Gweeds1980]

Interesting stuff... I hold a biology degree and in my first year conducted an experiment on biofilms and their ability to withstand a variety of treatments. We attacked biofilms (made up largely of cyanobacteria and e.coli) with a variety of known and supposed compounds. The most effective by far in terms of biofilm destruction was both lipase (biological washing detergent) and hydrogen peroxide. Interestingly N-acetyl cysteine both destroyed the biofilms AND prevented their creation in the first place.

Not sure of the practical use of either lipase or N-acetyl cysteine in a running aquarium, but certainly you could dump a whole load of h2o2 into a vacated QT which may be easier to do than take the system down entirely?

I would have thought lipase in the form of biological detergent could be used as part of the sterilisation process once the tank is taken down though?