what a nice display of different sword plants you have. My suggestion is based on personal experience only. I have about 10-15 amano shrimp in my tanks. I hardly ever see them but I know they are there because I rarely see algae. I love pleco still but honestly I think getting 10-15 amanos in your 72 gallon tank would be a far better algae control plan than another pleco. Amano's don't create near a fraction of the bioload (poo etc) that a pleco does anyway.