plecos wont be happy if the water is very cold, also grow huge.
bristlenose pleco, stay much smaller (6 inches tops) and shit a ton too (along with cleaning algae (somewhat, there is really no fish that does that to any real extent) (plecos can become much much bigger and bit troublesome)
but if your plants are taking up all the nutrients from the waste then the algae should stay minimal (only what started in there)
algae would be considered beneficial really, it can not compete with true plants and it eats some of the waste the fish produce along with producing oxygen, helping to keep the fish happy.