Ok so I have been having hair algae issues in one of my reef tanks and red slime in another and I was doing everything water changes didn’t help and then I noticed it actually got worse after a water change. I decided to make a fresh batch of water and mix with salt and run a test. Sure enough 1.8ppm for phosphate. I instantly went and bought new filters and I didn’t have a resin chamber so I added this as well to the system. Mixed up a new batch of salt water and still 1.7 with a TDS flicking between 0-1. What am I missing. I can’t do water changes to sort issues out because they just make it worse I am just using reactors to take the phosphate out atm. This is the RO system I use with a resin at the end. Vyair RO-1UP 5-Stage 50 Gallons Per Day Reverse Osmosis Water Filter System without Pump for Drinking Water, Marine Aquariums and Window Cleaning https://amzn.eu/d/f4T4ygA