Indeed! haha I usually don't listen to a word they say, but here we are. I got a cheapo one because I wasn't really anticipating getting one in the first place. The pump itself seems to be working fine tho. It is at middle water level and the tubing dips down into a U before going to the pump...so not sure if that makes a difference? I haven't had problems but buying a check valve isn't a big deal. I bought a new airstone for the hell of it and its working, so maybe it was the old airstone not the pump? idk can you recommend a good brand pump/airstone? The only other brand I've seen besides TopFin is Elite, but I've never used any of their products
Also I checked the manual and the pump itself and there doesn't seem to be a way of opening it. And the sheet says nothing about maintenance