If your water's ph is 7.4, and you're adjusting it that low, the first thing i would do is stop adjusting your water, seriously, stop adjusting it altogether, you do not need to lower 7.0-7.4 base ph water in soil that has "life."
This will also help raise your soil's ph if it's (likely) too low and causing lockouts/stunting. If your water contains chlorine/contaminants, that doesn't help either (use distilled if possible or at least filter it and let it sit out for 24 hours first).
You're over or under-watering if your leaves are drooping, nothing else is more accurate, wait until they start to droop, then give it water. A lot of people do just that, as a water-logged soil is not good and harms a young plant more over time than a temporarily thirsty one (which doesn't).