Definitely worth every penny to run GFO from my experience. Nuisance algae? What's that?!? It totally knocked out my GHA. Plus I only clean the glass once a week. I use 1/3 of a cup and change once a month, so cost is negligible.
The carbon keeps the water crystal clear and quickly soaks up toxins from chemical warfare or deaths of certain animals (anemones, sea slugs, etc). Same dosing and change schedule as the GFO, and the media costs half as much.
=== One word of warning, be very careful when you start running this stuff!! ===
First off, make sure you rinse both media's very well before adding them to your tank. I typically add media to the reactor, fill with fresh RO/DI and let it sit for about 15min (it takes a while for the dry media's to soak up the water and stop floating). Then I run ~2.5gal of SW through each reactor independently using old water from a water change. I just set the reactor up in a sink so it spills directly down the drain.
Second, start with low dosage and work your way up to "target" levels. As with anything in reefing, slow is key. Ramping up too quickly can easily shock your tank and cause big problems and / or death of corals.
And lastly, the stock sponges in the TLF reactors are too coarse for some of the finer media's like BRS ROX0.8 carbon and even PhosBan IMO. I use bonded filter floss cut to shape, and this doesn't allow as many particles to get back into the tank. The bonus of this is that flow will eventually slow down as this floss gets clogged up and your pump will start making a buzzing noise, which is an automatic sign that your media is ready to change! (this always happens at the 3.5-4wk range for me)
