Just a small update, thanks for the comments. I recently tried using acropower. My corals colours have improved, there is a slight reduction in phosphate levels though my nitrates are still undetectable. There also improved in growth but at the same time increase in algae which drove my phosphate lower due to available nitrates. It probably take some time for the phos to bottom out. Felt like I found a cure. I believe this will only work for tank that looking to increase nitrate and has undetectable nitrates and detectable phosphate.