Problem Leaves! Whats the Problem?

Mini spots.........looks like spider mite damage. Yellow tips is damage from hitting the soil surface at night when the leaves have been lowered down.

would like to see more of the plant. it's a mobile nute. Possibly low K ... would want to see how it progresses and any other symptoms to rule out other possibilities. seems way too early for Mg issues - those take 30-35 days to be visible AFTER the initial deficiency starts inside the plant. Is this plany a month or more old? Can rule it out if too young. the spots do look like pests suckling the leaves, but also can be early fugliness of first few sets of leaves. if that doesn't spread, not likely pests. if it's all over, inspect for pests. I think this is part of the other damage seen as opposed to pests. is their any 'honeydew' or glistening around the dots? not all will leave it behind, but that is a sign of pests (saliva or similar) the first 2-3 sets of serated leaves often have spots/blemishes that aren't related to pests or nutes. the more serious damage is something else.

Not sure what the white spots are maybe pests . Would take Shinsmillas advice on that.

Plant is adjusting to the Coco/pH. Happens to me sometimes on the first 2 leaves. Slight burn. If the new growth is healthy then your fine.

I would disagree with AsNoriu on pH being the issue here. As mentioned with that dose of root juice and humic acid, it would neutralise any pH issues. The soil does look wet and compact and could be a root issue, but with your feeding being low in N, that would be the 1st thing I try.

I think I can see the spidermites in the 1st pic. Look under the leaf. If you see reddish brown spots that turn into stripes as you rub over them gently, those are spidermites. The yellowing I'm guessing is lack of N, you can up your dose of bio grow because all your plants are looking very pale and drop the root juice. Root juice is mostly humic acid and that is great to neutralise any pH issues you might have. It's not something you need to use tonnes of and there is a lot of humic acid in compost, so a top dress of compost or a compost tea will have the same effect as the root juice or top max.

I would say too low ph. What caused it, could be many reasons. Your soil looks compact, damp and strange. Root juice is for first few weeks, btw its the only right doze by book ( in reality they offer to use it too long ) , bio grow - not enough, calmag in soil is rare needed additive, still doze absolute wrong from manufacturer ( i used it for 2 years with many grows, returned to other brand calmag, had troubles with biobizz ). Soil needs good saturation on watering day, but at same time needs wet/dry cycle. Lifting pots is only way to know when plants needs water again ... Tripple check ph and rethink watering habits. Good luck. Btw, i see some strange white spots, make sure you have no pests.