How to prevent mold growth in nutrient bottles

I cracked open my botanicare sweet bottle today and saw a huge green slime something floating at the top and knew i was fucked.
I’m going to toss the bottle and just buy a new one. Probably mold or something. Didn’t catch it cause I usually shake before I measure. Definitely a surprise to look in and see something looking back

I was wondering what I could do to prevent this from happening in the future. I use a pipette and graduated cylinder to measure out my nutrients and maybe I need to work on cleaning techniques. Any suggestions just cause I don’t want to have to be throwing away bottles of nutes that could have been used.

pre mix the nutes in a jar so they wont spoil

Oh wow. Thats gross. I've never seen something like that come out of a nutrient bottle.

I have to imagine thats severe contamination.

Im pretty relaxed when it comes to cleanliness, and I've had some nutes sit around for years in warm conditions and they've always been fine.

So you use your pipette to suck nutes out of the bottle? I think it would probably be better to pour your nutes out of the bottle directly into your measuring jug rather than dipping something into the bottle no matter how clean you think it is.

I use dry ferts for this reason