One could interpret the slimming as a sign of 'stress' or 'defense action' as opposed to corals 'loving it'. Maybe once in a while might seem to be a benefit, but several times a day?
Can you take a few pics of select corals now and again say in a month or so and compare with a pic post (growth, color, PE, stress, ect)??
I'm interested in this as when I do my bi-weekly WC's, I let the sump run dry with the return running while syphoning DT water into a brute can and I turn off the return once I see bubbles get blown into the tank. If I let the bubbles continue to run I see a similar 'slimming' effect like your video. It seemed like a stress / defense action to me....so I turn off pump once I first see bubbles in DT.
I wonder if there are any others that do this and can chime in?
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