I've lowered the flow rate to 50 mls/min which resulted in an effluent dKH of 11.5.  I'm going to see if display alk starts rising.  I've already got the ph set to 6.5 -- I'm wondering how much lower I'm able to go?  I mean, do people have their reactors set to 6.2, 6.3?  That seems too low?
BTW the corals I got from you a while back are all doing great!