Thanks, I'll try what you've said. I picked up a info sheet for Bio-bizz products from my local hydro and it has a feeding schedule for the plants life cycle on it. I noticed that during the flowering stage I should still be using a small (1 m/l I think?!) amount of bio-grow aswell as the bio-bloom. I switched to bloom only and this might account for the early N deficiency.

My problem with PH is that I got one of those aquatic types which is probably really good and it ranges from Ph 6.2 - 7.4 but I struggle deciding which colour I've got on the chart. If I could find some product that was Ph 6.7 as standard, I could make a test tube up for easier comparison.

Thanks again your royal dankness