Recently I have had a string of events (first hand), and other items I have read on forums that seem so basic, but I had either not thought of them or outright did not know. 1. If your display return pump is making a noise, rattle then you need to take it apart and clean it. Or clean the return pump during your routine maintenance. I kept adjusting placement and then finally took the pump out, the rattle was a shell lodged in the intake, not related to placement or a vibration. 2. Thanks to a new member I found out your can rid your dry rock of phosphates or unseen biological matter contributing to an elevated phosphate level later. Nope did not know this. 3. The biggie. Alkalinity and pH are exclusive from each other. If you have an issue and your Alkalinity is on spot do not take for granted that a chronically low pH (7.8) might be the culprit. Test for the low end pH, after the lights have been off for hours. Basically you can have a stable alk value and still have a significant pH issue. Correcting the pH to 8.2 24/7 (as able) made a HUGE difference in PE, reduction in algae and cyanobacteria growth. Inverts such as clams and anemones are much happier with a value higher than 8.0. That is why I love this hobby, you never stop learning.