Yellow edges of leaves

Zinc deficiency. A dose or three of soluble trace mineral mix, available from any decent garden center should fix this. Apply through the roots, foliar feeding is not advisable.

K, Mg lockout due to Ca excess and K, Ca lockout due to Mg excess

https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg Kinda looks like potassium. Would be better off knowing what they are growing in and what/how uch you are feeding them. A 500PPM of what is the question. and then PH also a great point. nutrtion might be there just locked out.

Looks like a fe, zn mn or mb deficiency, but this would be extremely rare. Trace elements usually aren't a problem in soil and if soilless, one of your nutrient products should contain them. you sure that pH isn't swinging? I don't see spots, so you can rule out Mg-deficiency. It's not startiing from the bottom or paling in the right progression on individual leaves, so N-deficiency can be ruled out too. Damage around the margins is often related to K-deficiecny, but this doesn't look quite right for that either. This is the problem with leaf symptoms. They are not discrete. More than one thing can cause similar symptoms. Unless your nutes are in some crazy ration, 550-630ppm should be on low side of things, although if this is measured by a TDS probe, it's not an accurate number. Calculate from your gauranteed analysis labels for an accurate value of what fertilizer is in your water. Free apps can tabulte it for you. If k is down near 100 or something, i'd wager that's it. bump up near 180 without changing too much of the other stuff.. If K is higher, then start eliminating possibilities. Do you have at least one product providing a wide range of trace elements? i'm assuming you are soilless based on the ppm info.. not too important to calculate in soil since a huge amount of unknowns exist in the soil.

Lokks like MG-deficit!

It sure looks like a N toxicity or burn of some sort to me. If your PH value is correct, and you’re growing in soil/mix, it is on the low end. Maybe your lights are adjusted too bright. Your DLI should be around 30 for veg cycle.