Confusion about formalin long term dosing

[Fishjunkie]

Another question you said something about filter media if i put a sponge filter in there wouldn't some of the brook live in there then when I changed the water and reused the media for the bacteria wouldn't that put brook back into the new water I'm sorry for so many questions and I thank you for your patience I just don't know all about treating for brook and doing all the ttm and keeping bacteria in there and all of that

 

[Jay Hemdal Verified Community Expert]

I've read to give the fish 48 hrs to recuperate between the formalin is 24 hrs ok? And it's just the rapid breathing they are swimming around not eating much but I guess bc they are sick but I did a ammonia check and it's showing yellow so no ammonia present atm

Yes - API ammonia kits are pretty bad, but I agree, that looks like low ammonia. It depend on your formalin dose - you mentioned two different ones. The low dose is good for 24 hours and then repeat. The higher dose is better to be used every 48 hours, but if you cut it in half, 75 ppm, you can do it daily and it will still be effective against Brooklynella.

jay

 

[Fishjunkie]

Yes - API ammonia kits are pretty bad, but I agree, that looks like low ammonia. It depend on your formalin dose - you mentioned two different ones. The low dose is good for 24 hours and then repeat. The higher dose is better to be used every 48 hours, but if you cut it in half, 75 ppm, you can do it daily and it will still be effective against Brooklynella.

jay

How long should I do the low dose like to kill off the brook like 4 weeks I have my tank going fallow so that's 6 weeks do I treat the fish that long I have a watchman goby would he be ok that long

 

[Jay Hemdal Verified Community Expert]

I think you should have the Brook under control within 7 days. If it isn’t, then the diagnosis is wrong, or something isn’t working with the treatment. Just double checking, you aren’t using 10% buffered formalin are you? The dose we’ve been talking about is for full strength formalin which is 37% formaldehyde gas in solution.
Jay

 

[Fishjunkie]

Yes it's formaylhyde incorrect spelling 37% 15% methanol

I think you should have the Brook under control within 7 days. If it isn’t, then the diagnosis is wrong, or something isn’t working with the treatment. Just double checking, you aren’t using 10% buffered formalin are you? The dose we’ve been talking about is for full strength formalin which is 37% formaldehyde gas in solution.
Jay