David,
I don't think accurate and the Kent doser can be used in the same sentence! Using it for RO/DI is fine, but it's not uncommon to overshoot or undershoot the sump fill line by an inch in a day. My sump has about 15 gallons in it when the pump is off.
I was planning on dripping the Kalk on the slightly diluted side until I was sure these swings weren't going to send my numbers too high. I figured I'd have to run some vinegar through 1-2 times a month to keep the flow steady. I'd test levels weekly and adjust with the 2-part.
I've seen a lot of posts lately wondering about how to automate Randy's 2 part. You might be able to set the drip rate close enough with the dosers if your consumption rate is stable, but then you would have to compensate for the evaporation rate with manual RO/DI additions I guess. I would like to get away from the AquaDose eventually for cosmetic reasons.
As far as the future of my lighting goes, I went with IceCap ballasts so if I decide to switch, I can just replace the endcaps and buy reflectors when my bulbs are ready to be replaced.