So I have a royal gramma in QT that was exposed to a fish that had uronema (and died). He never displayed any symptoms, but I gave him a 1 hr 250 ppm formalin dip upon tank transfer. After 3 days, prior to the next tank transfer, I dipped him again, but he only lasted around 15 min. He was lying on the tank bottom and looked dead. I got a net to move him and he would swim a bit then lie on the tank bottom again. This went on for a few min until he barely moved when the net touched him, so I pulled him. He is fine now, swimming well and eating well. My question is should I keep attempting to dip him since he was exposed to uronema? Or should the 1 hr dip have taken care of it? He is not displaying any symptoms.
Uronema and formalin dips
- Thread starter mitchrapp
- Start date
I ran the calculations and like you, I came out with 1 mL/gal = 100 ppm, but this University of Florida article on page 2 seems to equate it with 250 ppm:
http://fisheries.tamu.edu/files/2013/09/Use-of-Formalin-to-Control-Fish-Parasites.pdf
"For short-term baths a concentration of 250 mg/l, or 1 ml per gallon, can be delivered for 30 to 60 minutes."
It also says that for water temps > 70F, only 150 ppm should be used. I've never read that before.
http://fisheries.tamu.edu/files/2013/09/Use-of-Formalin-to-Control-Fish-Parasites.pdf
"For short-term baths a concentration of 250 mg/l, or 1 ml per gallon, can be delivered for 30 to 60 minutes."
It also says that for water temps > 70F, only 150 ppm should be used. I've never read that before.
ThRoewer
New member
milligram and milliliter are not interchangeable! Neither are ppm and mg/l.
Formalin is a nasty stuff and I would rather err on the side of caution. One member here killed a couple of percula by literally etching their skin off with 250 ppm dips.
Reading the article I found this:
According to them 250 mg/l equals to 1 ml formalin (assuming 37%) per gallon which is the dose I use.
It seems in some articles they just swapped mg/l with ppm which of course isn't the same.
Formalin is a nasty stuff and I would rather err on the side of caution. One member here killed a couple of percula by literally etching their skin off with 250 ppm dips.
Reading the article I found this:
According to them 250 mg/l equals to 1 ml formalin (assuming 37%) per gallon which is the dose I use.
It seems in some articles they just swapped mg/l with ppm which of course isn't the same.
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I'm confused now. So you are saying 1 ml/gal of 37% formalin is 250 mg/l, but that is only 100 ppm? I thought mg/l divided by specific gravity = ppm. In this case, the sg of formalin is 1.08 g/ml, so it should be around 230 ppm. I'm not trying to belabor the point, just trying to understand the dosage. In the stickies and elsewhere, I read that for dips, the dosage should be 200-250 ppm. In the scientific literature, I see 250 mg/l and I hear references to 1 ml/gal so I'm just trying to reconcile it all.
I am using Rid Ich Plus, which is 4.6% formalin. To get the equivalent of 1 ml/gal of 37% formalin, I need (1 ml/gal x 37/4.6 = 8.04 ml /gal) of 4.6% formalin.
To calculate this in ppm, according to the label roughly 5 ml 4.6% formalin per 10 gal = 15 ppm, or .5 ml 4.6% formalin per gal = 15 ppm. Therefore 8.04 ml of 4.6% formalin per gallon = (8.04/.5) x 15 ppm = 240 pm
So 1 ml per gallon of 37% formalin is around 240 ppm, which is in line with the recommended 200-250 ppm dips in the sticky and the 250 mg/l in the scientific literature.
To calculate this in ppm, according to the label roughly 5 ml 4.6% formalin per 10 gal = 15 ppm, or .5 ml 4.6% formalin per gal = 15 ppm. Therefore 8.04 ml of 4.6% formalin per gallon = (8.04/.5) x 15 ppm = 240 pm
So 1 ml per gallon of 37% formalin is around 240 ppm, which is in line with the recommended 200-250 ppm dips in the sticky and the 250 mg/l in the scientific literature.
Yep. I've dipped my other fish with the same and never had an issue. Incidentally, as I was going to dip the gramma this morning, before I added any medicine, he played dead on the button of the tank. I realized that the prior dip probably was not too harsh on him and that this is him playing possum. He lasted the full hour at 250 ppm this morning and is doing fine in the clean qt.
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