I wanted to say that in a nano reef, nothing will streamline your parameters like cleaning out the sandbed and rocks of waste, people buy dosers and offsets and filtration media solely to handle the leak that comes from that waste.
the other portion of nitrate and phosphate are your feed and bioload contributions which are ok for the system, no need to be offset.
for sure you can arrange flow to contact that substrate in a mesh bag, but no form of purchase can beat simply deep cleaning an aquarium that is accessible. The reason to do it is you can now feed triple better in a clean system, which isn’t backed up with waste already.
the nitrate reduction by filter method reduces feeding, so there’s less waste, leads to weakening corals as a risk. Lastly, deep cleaning refreshes a reef tank (allows more feed input) so even if incorrect nitrate measures are at hand there is no harm anyway.
you can’t believe how many people invest in nitrate binders where the measures weren’t correct to begin with, and coral bleaching + dinos results.