From the color I see, too much CO2. Target is lime green, but I think yours look like Lemon Yellow already

2 parts to the equation. Part 1 - lime green CO2. Part 2 - stable CO2 during photo period.
This means you need to start injecting CO2 before lights on. So once lights on, your drop checker is almost lime green. So maybe 1-2 hours later, it becomes lime green and stays that way until lights out.
You need to play with your setup - for me, I started injecting 2 hours before lights on, 4 bps (3 footer, 160 liters tank) and cut 15 minutes before lights off. Not saying you should follow my timing, but you need to find your own setup to try to keep your CO2 as stable as possible during the photo period.
If you have shrimps, observe closely. My shrimp activity, feeding, breeding - all drop like crazy. 3-4 weeks later, no sight of BBA.
I have since set my CO2 back to its original setup but a wee bit higher. Its been 3 or 4 weeks now - finally saw shrimplets during WC yesterday. I believe this is all related to CO2.
Good luck.
ic..i start my co2 2hours before light..off 1hour before light..the checker solution always giving light/clear color hence problem deciding too much or too low..
i think this is the proper target for me?.