phosguard dosing

[twoodrough]

Last summer I bought a 250ml bottle of phosguard from my LFS. It said to use 250ml for 65-100 gallons. A month ago I bought a 500ml bottle from Amazon. It says to use 85ml for 50 gallons. Those are drastically different amounts. Can anyone explain this to me?

I have a 20 gallon tank and need to know how much to use. I had a 10 gallon before, and this is my first time replacing the phosguard in this tank. I wanted to check my numbers instead of just doubling what I did before, and that is when I found the dosing to be so different.

Does the larger bottle have a different concentration? Did they change things since I bought the bottle last summer?

 

[Cecibella123]

I would suppose that -as you said- the different bottles (different brands?) have different concentrations of medication. IMO, I'd go with the directions on the packaging. LFS employees are usually a valuable source of info also. You could take both bottles in to show them, and ask their opinion.

 

[54seaweed]

Try taking a pict of the directions on both bottles and try to blow them up so the labels can be read . maybe someone with dosing smarts can help direct you to a safe level.

I've always used the phosgaurd granules changing them out every 3 months ,
I want to switch over to the liquid doser but every time I make a supply order I forget to order the doser ,

maybe the different brands are of different strengths as cicibella mentioned

be interesting to know the answer