No alk consumption during lighting period

[mattb2989]

Hi all. Puzzling 1. My corals aren't consuming alk during lighting period but as soon as lights start ramping down and during the night till lights back on theyre consuming. Any suggestions or ideas? Turned my doser off alk today just before lights on to prove my point and no consumption. Lights on at 12pm off at 10pm dosing equal parts alk every hour on the half hour. Testing on the hour so i know im not sucking up alk solution

 

[blaxsun]

It's the reverse for me (more during the day). Have you run any manual alkalinity tests just to rule out testing error?

 

[mattb2989]

@blaxsun yes mate