Rainsoft EC4 system on Well - regenerating but not cleaning tank

We bought a house 10 months ago that just put a EC4 system in prior to the sale as the old system was dead. Lately we keep getting yellow water from the faucets, and have to manually regenerate a couple time to try to clean it out.

I have noticed that the drain output during regen looks to be less than it used to be several months ago, but I don't believe it is a simply clog as the other 2 tanks flush with much more pressure.

Brine tank is full of salt, but the water level is very high.

I am thinking I have a valve clogged or filter. I just hate to call Rainsoft to come out to clean a simple valve or filter.