I grow exclusively w/ Gaia Green and 2-3 tbsp every 3 weeks for 10 gal of medium is a little on the light side.
I’m not sure how the soil was amended prior to starting, so a light feeding schedule could be ok.
On the other hand, if your medium was fairly inert and you’ve only given what you listed, they’re running out of gas.
I really need more details.
1. what was in the initial mix?
2. Are u PH’ing your water?
3. Have u flipped to flower?
4. Are u using tap water? Adding any cal mag?
5. Exactly what Gaia Green product(s) are u using?
I can get this sorted out for U with the right amount of info.
By the way, HLG is my fav…..not even close. My buddies and I do mirrored grow with everything being the same except the lights. The density and structure of the buds grown under the HLG is always superior.