I have two Echinodorus Osiris (Melon Swords). Ive had them for two weeks and they look nice and seem to be growing but both have developed a brown spot on one leaf. The leaf died on one and i removed it, the other i just noticed. I have some Foral Pride that was given to me but hesitate to use it as it has been sitting around for a couple years (so im told) and am not sure if its neccesary or not. Should i use it and if so, at the recommended dosage? Thank you.