Same seed, different shade.

Hello mate, probably the ligth one soffered more than the other the pH solution, i see from your diary you have the pH solution at 6.7, this is a bit high try to keep between 6.2 and 6.5. Good luck and happy journey!!

Think of it like brothers and sisters from the same parents. You don't normally see two sisters who look identical. they have some differences, Same with Cannabis from the same pack of seeds. This is whats known as the Phenotype. little characteristics that set them apart. Its also why people do a pheno hunt to find the best of the best for clones and such. Overall nothing to worry about, just how they are. They are two lovely shades of green. My screens "night light" is on making the pic more warmer to offset the blue. so I am not seeing it true to form. Good Luck!

With two parents of different colors, it happens that the children are lighter or darker while still having a resemblance. It's a small difference in phenotype. By the way, if you rub your fingers on the branches, they should have a slight difference in smell I think 😉

I had two Banana Purple Punch Autos side by side. Same soil. Same light. Same nutrients. Same temp and humidity. One grew sparse, greater inter-nodal spacing, low yield but dark purple buds. The other grew dense, lots of buds but no purple buds. Just looking, you'd never know they were the same breed. Folks here taught me it was due to different phenotypes. Illustrated by the sibling examples given in the previous answers.

Even though they may be the same breed of seeds they will always be slightly different. You are seeing this. Think of it as siblings from a mother/father. Alike, but not the same. How to get the exact same plants is to take clippings (clones) of one and they will all be the same. Hope this helps.