I installed a biopellet reactor a little more than a month ago and I haven't seen a reduction of nitrate at all. Just curious as to how long others have waited before seeing results, I know they can take a while.
There are several variables here but I didn't see any decline for just over 2 months. Then it took about 4 more months for my nitrate to drop from 80ppm to about 5ppm. This is a slow process but it will work.
Just remember to turn off the reactor and note the level of the bio balls. You'll need to to replace the balls back up to this level every few months.