Caulerpa & pH

[kermit the krab]

Lately, my pH has gone really high like 8.6 and has stayed at that level day and night. My caulerpa has really grew so densely in my refugium that I plan on removing more than half of it because I thought I read somewhere that it can cause pH to rise. Does anyone know if this is true?

[dark horge]

True, but it also depends

Algae take up CO2 in the course of photosynthesis, and this means reducing the amount of carbonic acid in the tankwater.
Normally this is a good thing, as the tendency of any hobbyist tank is usually to acidify over time.

I do not know if your Caulerpa are indeed solely responsible for your pH spike, though. Backtrack and see if you can remember any other events or routines that may be pushing your pH up.