Let’s say you had it at 100% then 1ml would be enough for 1M ml =1000liters
Therefore at 45% 1 ml would be enough for 450 liters
You have 300 liters, so 2/3 of that.
Solution:
Get a cup of water add 1ml and mix
Drop 1/3 of a cup of the mix
Add the remaining mix to your water. Problem solved!
You...