PH issue

[sjslanina1992]

Hello. My pH quite recently has dipped to the lowest it's ever been. Generally my pH dips to 7.8 during the night and then peaks at 8-8.01. I have every window open in my house to get some oxygen saturation which is what I normally do if there is ever a small dip but I can't figure this out. Included are my pH readings and my weekly tests. I also do 10-15% water changes weekly.

Anyone have any idea why this drop is happening? I originally assumed it was my dKH was significantly low, but I tested and it's within my normal range. Also the nitrate spike was me killing bryopsis in my tank. Did a 30% water change and readded red ogo to my refugium which is sucking up all my nitrates

 

[jda]

It is probably a testing error if the inside of the home has the same ambient co2 level as outside AND you tank has proper gas exchange and aeration. If you have a good skimmer, then this is likely enough gas exchange.

Do you happen to dose any strong bases like calcium hydroxide?

pH probes are probably the least reliable piece of equipment in any reef system. They just drift for no reason and fail all of a sudden.