I know that this is hardly a new question; however, I am wondering what the best remedies are for this situation: I have used Flourish Comprehensive for micros for sometime prior to deciding to go with dry fertilizers and make my own liquid fertz. Unfortunately, I have found that bottle containing the Plantex CSM+B is has a fungal-mold related problem. I know that this is a common problem with CSM+B and some folks refrigerate their bottles; however, I recall hearing that there are other alternatives to refrigration (which besides cold is dark).
I have the liquid solution stored in graduated dispenser bottle
and it is stored under the cabinet; however, it is not entirely light free as the back of the cabinet is somewhat open and it is probably dimly illuminated. Obviously, the dispenser bottle is transparent enough to let the light into it; whereas, Flourish Comprehensive bottle is non-transparent. Flourish Comprehensive does not require refrigration nor dark storage (though the bottle is not transparent).
So, I guess my first question is what are the options for fixing the problem. Second, I was wondering whether it is simply a light tight bottle or whether their are inhibitor-preservative agents one could add that are not harmful to fish (e.g., Flourish Comprehensive just fugal-mood free because light-tight or is there fugal-mold growth inhibitor in the mix as well).
Thank-you, in advance, for taking a moment to help.