must be the bad 660nm... afaik.
Oh ,common now ....High root to shoot ratio isn't always a good thing ...
And yes , for this amazing rootball ,660nm leds ,probably 've contributed enough ...
(Still we do not smoke the roots .... But anyway ...Good root system is needed for good yields ..
And that root system is amazing ! Lots of biomass/energy was allocated there ...IYKWIM...
)
Edit :
-That's why I'm betting on the new one ...
...More balanced and full red spectrum there ....
Not only taking care the roots and PS I / ChA ,
but for the leaves and PSII / ChB also ....
I'm telling you ...
It's a champ !