Got another Waterpik system because I do love this unit. Although I thought everything was going properly and I was removing the brush head every day to clean without a problem, the problem started after trying to install a new brush head that was due. At first I could not get the new brush head on and was getting frustrated. However, I found that if I ran it under warm water I finally got the new brush head on. Yeah! Went to use the brush and then remove it to clean it and that's where the problem started. I cannot remove the brush head which means that I cannot replace the brush head in 3 months time. Is there a "trick" to get this brush head off without breaking the unit like I have in past systems that I bought?