Fixing ReefCrest bug

Limiting ReefCrest so it doesn't go over 100 when pump is configured for
anti-sync.

I had DCPump.Speed set to 100 and the anti-sync pump was getting values
up to 120% since DCPump by default uses 20 as the offset for ReefCrest
mode.  Just added a constrain to prevent someone from making same
mistake I did.