# erythromycin and CRS



## Aquadawg (Aug 18, 2012)

Just turn your lights off for a few days. No need to cover the tank.


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## g4search (Aug 10, 2014)

RoyalFizbin,

I think that everybody here understands that you are hesitant to use erythromycin in your shrimp tank because you have not used this before. (Perhaps you may want to take the CRS out of the tank before erythromycin treatment?) While I have no experience with shrimp, I can assure you that using Erythromycin* is the best way to get rid of cyanobacteria, since it kills 100% and does not effect other things in your tank like: plants, algae, fish, shrimp, or snails.

A dose of 1 mg/L is effective, but I recommend to use about 5 mg/L. So a 200 mg packet is just right for a 10 -15 G tank. Even though you don't need to, it is a good idea to remove the bulk of the cyanobacteria from the tank, otherwise you will have brown masses of dead bacterial debris in your tank after the treatment. 
Also, what is very important, if you have an "activated carbon" or a "Purigen" filter, take the filter material out of circulation, but do not remove it and do not stop the water flow. (Taking the filter out of circulation is recommended to prevent the activated carbon, or other resins, to absorb erythromycin from the flow-through water).

Procedure
Dissolve the 200 mg of EM in a cup of water (stirring etc) and pour it into your 10G tank. Let your aquarium water then circulate through the tank for a minimum of 24 hrs, although 48 hrs is recommended. During this time you will see the cyanobacteria "patches" breaking up and turning brown, a clear sign that the bacteria are now dead. After the 48 hrs water cycling you should re-insert your filter material and start circulating the water through the filter. This will now absorb the remaining erythromycin and other organics. If you wish, you can do a water change, but it is not necessary.(discard the carbon resin sometime later)

Your tank is now free of cyanobacteria, but you should take care and be cautious with anything that you add to the tank, since this is a sure way to re-introduce cyanobacteria.

Best of luck.

*Erythromycin inhibits the growth of bacteria by interfering with their protein synthesis. (It binds selectively to the 50S subunit of the bacterial ribosome and thus inhibits translation of bacterial mRNA that leads to cell death.)


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## ShyShrimpDoc (Jun 28, 2012)

A few nerites and a uv in the filter line will take care of it without the chemicals. Erythromycin should be ok on the CRS short term. A UV off a site like ebay isn't that expensive and will help with both algae and bacterial control in the long run. I put mine on a timer, 1 hr periods 3 to 4 times a day. You can even kill it off the plants by sweeping the bulb over them. Protective clothing and especially eyewear is strongly recommended. Without eye protection you get a version of snow blindness that is brutally painful. 

Having done several antibiotics in crystal shrimp, you may lose a few even on short dosing. If the erythromycin affects your nitrogen cycle, you will lose more than a few. I have never used that one in specific so I don't know. Plus different tanks have different species of bacteria running their nitrogen cycles, so it's not 100% predictable. Most tanks have several types of bacteria involved in the process once well established, so the older the system, the less likely it is that there will be a problem with the nitrogen cycle.

Bump: Also, I'm a little confused. I thought most algae was a form of cyanobacteria, so how it will kill one algae and not another is beyond me. I have obviously never used antibiotics for this. I believe they should be reserved as a last resort to avoid creating resistant strains of pathologic bacteria. But that's just the med student in me.


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## RoyalFizbin (Mar 7, 2006)

Blue green algae (BGA) is cyanobacteria. Other algae's are true algae. I read that its only necessary to dose a half strength to kill BGA. Many people think that half strength is enough to kill BGA but leave the biological filtration unharmed. 
A UV filter wouldn't do anything for me now. It would be good to prevent the algae from growing in the first place but now that its already in the tank, there is nothing that the UV filter would do to kill algae that doesn't pass over the light. As for Nerites, I've had them before and would never get them again. They leave all sorts of hard white eggs on everything. I have pieces of drift wood from 5 years ago that still have some remnants of the eggs attached. I scraped most off but the ones that I missed are still there.


g4search,
Good thing you reminded me about the purigen. I'm not totally sure purigen removes medications but I'll remove it anyway if I try the EM power. The API box says that each packet is 200mg and treats 10 gallons. I think I'd go with half that concentration. For now I'm trying the leave the lights off suggestion.


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## g4search (Aug 10, 2014)

RoyalFizbin,

that's the wrong idea. Most people think that way, because they look at antibiotics as a generally toxic compound, similar to say copper sulfate. I have seen videos where the guy in the fish store suggested to use "half" the strength of erythromycin, if you are not sure. Not good to spread this message.

For antibiotics this is really the wrong way to go. What you need to do is go with the maximum dose first, then you can continue with a lower maintenance dose if needed. Unfortunately, this is done wrong so often that there is a real fear for resistance. It would not happen, if people were doing it right.


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