Does anyone use this? I currently use an RO/DI but I'm planning on doing a 50% water change tomorrow or Tuesday because I have high phos levels so premixed saltwater would be much easier for such a large change. I'm just curious if the phos levels are low, I have prime so I'm not all that worried about the other levels because I can add it and mix it up before putting it in my tank but phos levels are completely different. Let me know if anyone's used it