I recently experienced about an 8 hour power outage. I do not have an automatic battery backup (which is changing very soon), but I was close to home when it happened and I was able to stop and get a power inverter to run my return pump on low for about 6 of the 8 hours. When everything came back on, my pH was low which I expected. My other usual parameters that I test were in line (SG, alk, Ca, Mg, PO4, NO3) but is there anything else I should be keeping an eye on? This was my first major power outage. Thanks!