Starting to yellow

Yeah, more likely too much light. It's pretty difficult to have that sort of deficiency this early. Plus where it is occurring is a signal it is light related too. if you have a proper light for the size of your tent, even more reason why 24h operation might have done this. it's not about "more" light... it's about the right amount of light relative to environmental variables - primarily co2 but temp and rh are big factors too. Read up on Daily Light Integral - DLI - the wiki is sufficient information. You don't need to memorize the math, but understanding it is proportional to hours of operation is key. you can google for DLI tables that already do the math for you based on PPFD and hours of operation. you want 35-40 dli for ambient co2 (at diode* with typical hanging distances for current LED grow lights on market). Regardless, you can get there without the math by observing and adjusting -- whether it is light damage to the leaves or how much distance develops between growth nodes, you can dial in your light very easily and once oyu do that, it'll be roughly the same each grow after -- a few percent either way may need to be dialed in as variables are not always the same grow-to-grow. it's not about the hours .. it is about the DLI as to whether you are over-stressing the plant. E.G. a weaker light can be run 24h with zero problems. The plant can only do so much photosynthesis per day - primarily limited by CO2 intake. giving more will cause damage to the plant -- giving slightly too much might takes weeks before you see symptoms. So, keep notes. Don't assume the most recent events are the cause of what you see, because this stuff takes weeks and sometimes months to be visible (more so with nutes as far as 'months' of time to see ramifactions). i'd suggest moving away from grow dots and similar slow-release fertilizers. if you make a miscalculation, there's not much you can do to fix a problem with a grow-dot-grow. if you do learn to ride that bike, it does have some benefits, obviously, but you may have a few shitty grows before you learn that balance as to how much to add. but, i also doubt they have a great ratio of nutes. much better to have 2-3 components to your fertilizer that allows you to adjust NPK ratios based on how the plant is growing (visible symptoms etc). You'll know more about the amount of dots you added in the next month or so.