After three months I would have expected to see a problem by now. The tank is low light for most of the time and I'm only injecting CO2 during the high light period (and slightly before and after).

I've run the tank for years with the standard CO2 for the whole daylight period, and now I'm trying something different. What have I to gain? Nothing really except less refills and less trimming time.

If I get an algae outbreak I'll rethink my strategy. I'll make a post if that happens, but until then I'm happy with the way it is.