The older leaves start turning yellow after a few days with the temperature above 90 degrees. It has an immediate effect on kovachii of all sizes. If I can avoid this, mature plants can accumulate 3-4 years of old growth and will bloom every year. The granular limestone I use is about the size of fine sand. It doesn't wash out of the Orchiata as quickly as powdered dolomite.
My first kovachii were slow growers, but all of the recent flasks, mostly from Chuck Acker, have been very robust growers. I think these flasks are 4th generation US kovachii and my oldest plant is 2nd generation US kovachii. Mike