I had a reactor like that plumbed into my last 2 big systems (425g and 220g) but never saw the need to use it. If I had had a problem I have carbon, GFO and phosphate removal products sitting on a shelf... but I've never seen the need.
So my new system is a 40g DT with a 40g sump/fuge. This time I plumbed an extra outlet from the manifold with a gate valve, but I left the reactor on the shelf with the chemicals. That was over a year ago and I just had my RFA's deliver 20+ babies. I only change the filter sock about every 6 to 8 days (just before it starts to hold water inside deeper than the water it's hanging over) and I only do water changes every 6 to 8 weeks. Heck, on the 425g system I didn't do a water change for nearly 2 years. But that system had two 45g refugiums, a huge skimmer, a 45g DSB with 10" of sand and 100 extra pounds of live rock!
My advice is to set up your system so you can use the reactor if you need it and have the chemicals you might choose to run ready on the shelf. But there is no need to run any chemistry unless you see a real need for it. It's kind of like the over use of antibiotics use for humans.