Biopellets exausted?

Can biopellets actually become exausted before dissolving? I have had mine in my reactor for a good 6 months but my nitrates are still around 25. When I first added the pellets I had a huge GHA outbreak, all the GHA is gone but I heard the pellets can actually be exausted and in need of replacement with new ones. Anybody know if there is any truth to that?

 

Yes my NPX say to keep your reactor toped off between every 3 to 6 months.....so I guess you should have marked the original level before adding water.....then keep them at that level

 

You should mark the initial level in the reactor then top off when there is a noticeable reduction.

 

When you add more make sure to go slow, you don't want your levels to dip too quickly.

 

I guess I should have mentioned that yes I have been topping them off but the nitrate levels seem to have came to a steady spot and wont drop anymore.