I have a 125 gallon aquarium and have been looking for a cheap fertilizer. It is heavily planted with a professional co2 setup. I need a fertilizer that doesn't have copper because I have 21 nerite snails and can't afford to lose them. i am currently using seachem excel and its quite expensive. I would prefer to use a liquid fertilizer because I can easily inject it into my roots in the sand with a syringe. Also interested in dry ferts, whichever is cheaper and wont hurt my fish and snails. Suggestions?