Having run
Happy Frog many times, my guess is you're over-lit, over-fed, and over-watered.
Light: When I run LEDs, I hang them at the top of the tent, and manage intensity with the dimmer, ramping up to 50% intensity at the end of veg. Then I bump to 75% in the third week of flower, and 100% in week 6 of flower. If the plants show they want more or less light than that, I adjust.
Water: Over-watering is watering too often, as opposed to giving too much water at once.
Happy Frog holds onto water pretty hard. Adding EWC increases that. I'd water slowly to runoff/saturation, then let them dry back until the pots are very light. You're in big pots with small plants. A proper dryback could take two weeks or more. That will get shorter as the plants get bigger.
Feeding: HF usually comes well amended out of the bag...runoff of 2500 ppms or more, sometimes. I wouldn't feed until runoff was 1K or lower. It can take three weeks or more to get there from new soil. It's also possible to get bags of HF that are less amended...so keep an eye on your plants for signs they're hungry.
Not claiming my way is the right way...it's just one way that has worked well for me. Hope that helps.
