I currently have a 20gH aquarium planted with various crypts(parva, lutea, spiralis, and wendtii) stocked with 6 Bronze Corydoras, 7 Harlequin Rasboras, 3 Otocinclus, and 1 Pearl Gourami. I do Bi weekly water changed of about 25% and all my fish seem healthy. I was talking on another forum and...