Tiny Bubbles .... in the Tank

[Beverly]

Ever since we changed from using a pair of Hamilton 175w 10,000k bulbs to two Ushio 175w 10,000k bulbs, we've been getting tons of microbubbles in the afternoon and evening in our 120g. The MHs are on only 9 hours a day, with PC and NO actinics on for 12 hours.

This tank has no sump, refugium or skimmer to generate bubbles. The bubbles appear to be the product of photosynthesis and are probably bubbles of O2. Anyway, they are annoying me, but corals, BTAs and fish do not seem to be bothered.

Any ideas about reducing these bubbles? Out darned bubbles, out!

TIA