of course...but then we're just saying to check the water...it would't hurt. Nothing could be wrong with the water. But for me, IMO if a xenia pulsed before and it's been pulsing...and then it suddenly stopped and everything else is constant (light, flow, position)...then maybe there's something slightly off with the water (salinity, nitrate, phosphate, iodine-i don't this one's really needed, nitrite, amm...etc.etc.).