Your right. Most people put way too much glue and or primer, and it turns out looking like crap. I have been glueing pvc and or cpvc for 30 years, I have never used primer. If your pipe is clean why bother. I have only had two leaks that I can remember, and both were because of water in the line. Fish tanks are very low pressure and are unlikely to leak if you make a complete circle with glue and twist the pipes. I have glued pipes many times with pressures over 100psi and never had leaks. The point is why use all that purple runny crap..