No, it shouldn't affect your water chemistry at all. If anything, it's what's keeping your nitrates at zero, since algae consumes nitrates. Instead of adding pH stabilizer, which i advise against since adding chemicals to a SW
tank is not needed at all, try doing a water change larger than 5G. 5G out of 125G is practically nothing. Try doing a 10 or 15, even a 25% water change. Also, do you have enough surface agitation? Try pointing a powerhead up at the water surface so you get good agitation.