it had been 0 a few days before though :dunno:
I didn't have the 2 tests side by side, should have done.
I didn't understand properly till after I'd meth blued the tank that the nitrifying bacteria would die so I presume that is the result of the spike. If I had realised I would have tested the water during the week.
Hopefully she will improve overnight. She wasn't flashing much and certainly not when I visited her just now after a spell in the other tank.
In the nitratey tank I've dumped a load of moss, that should bring the level down again shouldn't it?