I don't know anything about the product you're adding, but regarding pH:
1)meh, it's not that far off. This is when people are going to tell you not to chase numbers.
2)You can bump the alkalinity more. Again, I don't know anything about your product, but using a normal Alkalinity supplement will work just fine. 8.3 is fine, but you can go a lot higher and if that's what it takes to get your pH where you want/need it, go for it.
3)I see you're checking pH at different times. Make sure you understand that your pH will fluctuate with your lighting schedule. It's perfectly normal, for example, to see your pH at 8.00 in the middle of the night and 8.3 in the middle of the day after the lights have been on for a few hours. I'd suggest, at least for the purposes of monitoring and adjusting the pH, check it at the same time each day. I mean, check it all you want, but pick a time and use that to see how it's trending. Preferably, at a time when the lights have been on for a few hours.
You can see the effect the lights have on the tank in the chart. Notice how it's the pH is low at 7:30am and higher at 7:30pm.
4)Make sure you're not testing pH right after adding something to bump alkalinity.
5)If you have a skimmer with an adjustable air intake, see if you can turn it up without it overflowing. More bubbles means more pH (kinda). If you can easily run a hose from the air intake to a window so it pulls in fresh air, that'll probably make the biggest difference. If you can't do it easily, there's a very easy test you can do to see if that's something worth putting work into doing. Similarly, you can look into a CO2 scrubber. But again, I'd make sure it would even help before investing in it.
