I replaced my old water softener yesterday with a new one. The difference between the two was the age. The old one come out and the new one went in to the same lines. With the water in bypass I have great water pressure throughout the house as soon as I turn the valve to service the water pressure drops dramatically throughout. I can't flush the toilet and brush teeth (not that I do that often) at the same time.

I have read all the posts about the problem being the resin in the softener, but with this one being a new unit it should have nothing to do with the resin. There are no leaks, when I run the softener through all the stages of regeneration everything seems to be working. Any Ideas?

What brand did you install? Call their tec department and ask why its doing this.

I got it figured out. When closing the valve to the house I inadvertently snapped the inside of the valve while in the almost closed position. Fixed that and now things work.