I have a big problem I’m pretty sure. I tested my phosphate multiple times throughout multiple days and it’s been above 0.9 I’m not sure exactly what it’s at since my Hanna checker only goes up to 0.9 so I at least know it’s above that. I tested my rodi water and new saltwater and they were both at 0 or 0.01. The tank is newer or new to me I got it a few months ago and moved it to my place and kept all the old sand and rock I did make sure to try to clean out the sand as best as I could. I am very concerned about my tank and being new to the hobby I’m not sure what to do. Any tips or advice would be much appreciated.