I have 2 Aquaclear 70 powerheads as part of a river manifold setup in my aquarium. I chose this brand, because they had reputation for quality and had longer life according to reviews. They run only since July and were very quiet at first. Now (in last week) one has become louder and there is almost a slight rattling sound. I assume something with the impeller?
I have sand and gravel substrate, but intakes on the manifold are sponges and the powerheads are positioned high enough up, that I doubt, that sand could come in them.