Very serious question...

So I was checkin my ppms alil bit ago and I seen a tiny clear bug walking around ontop my res? Not sure what it was n it was escaping so I killed it before I could get a better look...

Any ideas?

I did have rust spots forming on lower leaves a few weeks ago but i hadent changed my res in over a month so I flushed and added a calmag dose. Those spots have stopped since then but I did have a few leaves get pastey and die (lower leaves) then I noticed leaf tips going brown and edges to which im sure is overnute... But ive been checking all undersides of leaves which is hard w 60 plants but see no webs or bugs of any sort.... Ideas? Anything? Wouldnt i have noticed spider mites within 3 4 weeks? And wouldnt they have done more damage?
Any help greatly appreciated. Im still examining leaves...

;Oh and the orange spotz im referring to happened to one strain... And I look closely and there is little pin sized spots occasionally on leaves but all the ones tht have it have nute burn on tips n edges n they also have splash sized crispy blotches ranging from one mm to a cm? Possibly jus nute burn n the bugs freakin me out? Like I said no bugs or webs undersides if leaves look fine... Also rooms never above 80 and night its like 65 plus during the day they have central air comin in the middle of them thru the bottom. I was considering a chop and freezing to kill them if I notice anything? They got 2 n a half weeks left on half and 4 weeks on other half.