howdy!
i'm going to have a 100gallon reef, mostly softies and lps, but also some sps. i'd rather have a nilson reactor because it just seems like less of a hassel. what do you guys think?
All depends on the calcium and alkalinity requirements of your tank. If you have a lot of heavily calcifying animals in your tank, a nilsen reactor may not be enough for you to keep up with your calcium demand. Each have their own benefits.
IME one thing to be cautious of when just running the kalkreactor by itself is that they produce very saturated (and potent) limewater. Initially, you may not want to top-off all your evaporation with it as that can drive your pH way up. High pH + high Ca/Alk levels + fine aragonite sand (especially if it's not well coated with bacteria) can cause clumping problems.