Quote Originally Posted by worley
If the 'trates are still high, you could do a bunch of water changes to get them under control then let the scrubber do the rest

Tried that before. It works to a point but, as I say, the tap water around these parts has around 40ppm NO3 so water changes are never going to bring it down below that.

I used to use live plants to keep the nitrates down, which worked to a point, but I now have a number of metynnis argenteus which leave less vegetation than a plague of locusts.