I disagree about a recirculating pellet reactor being a 'necessity'. Yes a recirc reactor allows you to control the discharge of the stripped out water so you dont rapidly deplete your system sending it into a toxic freefall. But that can happen with anything we as reefkeepers dose or add. Need to start off slow. If I was to set up 5 GFO reactors on my system to wipe out a phosphate problem overnite, it would be just as detrimental. Same as dosing vodka, soda ash or anything else for that matter. You need to make minute changes.
For instance, i modded a TLF 550 to use as a bio pellet reactor. My total system volume is around 325g. All in one bio pellets states "500-1000mL of biopellets is recommended per 100 gallon" So by those guidelines I should use 1500-3000mL of pellets. Nope. Start out slow. i added 250mL to start, let it run a few weeks. Added another 250mL. Now after running for 2 months, I just added the 3rd bag of 250mL. After 2 months I am now at 1/2 of the recommended usage for my system size. I am still experiencing high Nitrate (~40ppm) and moderate Phosphate (+-0.06) but everything is healthy, all coral is coloring and growing in a weedlike fashion and I havent lost any inhabitants since I started. I also run a cup or so of GFO through a MR1 reactor and have been dosing vodka for 3-4 months.
My point is all changes must be done in a tank in a slow fashion. If you are looking for a quick fix, you are in the wrong hobby. A expensive and or complicated piece of equipment such as a recirc reactor isnt a neccesity, it just helps to err on the side of safety.
FYI, I have a predominately SPS system and a medium to medium-heavy bioload.