The Hydros controls the dynamic dosing. Both are using the alkalinity readings but there is less of a change on All For Reef since I have the range set from 7.5-9.5 and the range on the KH buffer is 8.00-9.00 If the reading was at the low number you would get the largest full schedule dose dose divided by the number of doses. On the other end you would get the smallest full schedule dose divided by number of doses. I say it that way since a schedule might not last a full day. It can be set any time frame and even have it skip specific days of the week if you want. If a reading is in between the high and low readings it would be adjusted depending on the value so the higher the reading the lower the amount dosed and the lower the reading the higher the dose until it reaches a limit then it wont go any higher or lower in the dose amount. If the reading is trending lower than where I want it I can raise the higher and lower amount some or do the reverse if the reading is trending higher.