SANLIGHT - 1st Grow

I would doubt you ruined it. Look up schwazzing. In this case, it depends on genetics and environmental conditions but you could have increased your yield. It's all very hotly debated, so I suppose you will see at harvest.

70% is way too high for flowering. 30-50% range is ideal. PH is at the low end of the spectrum, and wouldn't hurt to come up by .2-.3 temp might be a bit high for flowering as well, ideally 19-22. Feeding K helps bloom yield, but should impact leaves. Normally at tend of flowing the leaves start to look like you sucked the color our of them from the main stem with a syringe, and the spotty yellow isn't ideal, but probably isn't a huge issue, and is more likely cause by too much nutrients than too little and spotting and tip browning can be symptoms of root burn.