Bristle nose pleco's are great, but will eventually outgrow your tank. Rubber nose pleco's are much more sensitive to higher nitrates in my opinion, but don't get as big. If you're not injecting CO2, Excel helps with algae growth (especially black beard algae) and is beneficial to the growth of the plants. I use it in all of my low tech planted tanks. I would second the suggestion of introducing 2 or 3 nerite snails. They can't reproduce in fresh water, and do a pretty good job cleaning things up. The only down side is that they WILL lay eggs that tend to solidify over time, and are noticable in the tank.