I use an Aquamaxx TS-2 sulfur denitrator and am very pleased with it. Once it's cycled and drip rate is dialed in, the maintenance is minimal. Every time I am under the tank, for example to change a filter sock, I just check it quickly for drip rate to make sure nothing has become clogged. The media replacement frequency is advertised as every 2 to 3 years.
I run mine outside of my sump, drawing water from the sump's second chamber (if you count the filter sock chamber as the first) and back out to the sump's return chamber.
If for someone reason you don't want to keep it as a denitrator, with an additional purchase, it can be converted to a calcium reactor - although you wouldn't need a calcium reactor in a fish only tank.
The water coming out of it consistently tests at 0 nitrates.
In order to be transparent, I think it's important to note that I have multiple direct and indirect nitrate interventions in place. I do use a protein skimmer. I daily dose ESV transition Elements plus. I have a Brightwell Aquatics Xport NO3 - Dimpled Brick in the sump. I run Chemipure Blue in a media reactor. My filter socks are left in the sump for two hours a day and then removed. On water change days, which occur every 10 to 14 days, I stir the sand and blast the live rock with a turkey baster , as soon as the water change is complete, I add fresh socks and let them go until the AM, about 12 hrs.
I "over feed" as many might think, feeding between 4 to 5 times a day with various frozen foods in small quantities each time which have been soaked in Selcon or the equivalent. I dose phytoplankton and amino acids. I target feed my corals two or three times a week. I believe good, varied nutrition provides healthy, robust fish and corals. I also believe it reduces fish to fish aggression.
My nitrates run between 2 to 3 when tested prior to a water change.
