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?