well if yo ulook at the Sulphur reactor it takes around 3-4 days to get it going when you used the proper media. you can have bare bottom tank with lots of flow and not have to worry about the Nitrates in your tank. the reactor will take them out for you.
Coil reactors take about 4-5 weeks to get going . and you dont need asand bed you can have Bare bottom tank. same same with the coil reactors to they work the same way as the sulphur you can have a Bare bottom tank and feed and have lots of flow.
DSB works great but you have to wait like 2 moths for it to activate and then you need clean up crew, to keep it clean, you get cynao from the sand bed. where does all the crap from the fish goes it has to go somewhere. it just stays in the sand and accumulates.
So at the end of the day, people are starting to use the Sulphur reactors . more its a easy and quick way to drop your Nitrates fast .
BUT WATCH OUT FOR YOUR ALKIN THE TANK IT WILL DROP