Mine has slowed down over time but then I'm sure I need to clean it out. I really like the random current. My only complaint with the SQWD is that you can easily overtighten your hose clamps. I cracked my caseing but then fixed it with epoxy. Just and fyi to be gentle with it.
I have mine within 6 seconds. Not enough. Too fast. The flow barely reach the other end of the tank because the other end already started. Its good if you direct the flow from the front to the corals. It could be used directly and not indirectly. JMHO.