Odd leaf tips

Hey guys I'm on the way to the store to get a 30x mag glass to get a better look but would also like to kno what I'm looking for. I have week old seedlings and one is showing discoloration on the tips of the leaves, hope its just light issues/ a deficiency and not fungi/mold. thanks in advance for any info, newbie here.

What would be some telltale signs to look for with mold? They're so young I doubt it is deficient, however I am using RO water...

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Some better pictures

Looks fine give it some time before you worry. Maybe the soil is "hot" with nitrogen and caused a nute burn.

It's not even old enough to get fungus or mold. Lots of baby seedlings have the first couple sets of leaves with some discoloration.

Awesome, thanks guys..just trying to make sure she's healthy..I kept the humidity dome on like an idiot cuz I figured I needed to maintain a wet environment cuz I live in a desert. However after some further research I guess that's not a good idea for dampening off and future fungi reasons..what is a good level of RH for baby beans? Thanks bloke, and again aim aim..ur always a help
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I looked at the leaf tip under 100x microscope and discovered white hairs on this tip that had turned grey..I'm no expert but considering the humidity levels spiked at night, and looking at powdery mildew pictures online under a microscope, I wasn't gonna take any chances..I took this bitch outta my show and sprayed the remaining crop with baking soda/water mix..lowered humidity levels, increased my poor ventilation with a can filter and multiple fans after removing the bitch with dirty tips, plus chopped some tips off of another questionable spot. Now I'm just praying...any other advice besides better growing conditions? I think the humidity dome/ high r.h. plus poor air circulation started this.. hopefully better air + humidity levels keeps the PM under control...