Yea, you can let it eat the cotyledons and then start feeding, but coco has pretty close to zero nutrients for plants. One benefit to starting mutes asap has to do with feeding your cocos cation bank.....
What kind of coco? Eh nevermind since you boiled it you probably destroyed any buffer it was given, feeding nutes will replace it, but over time and you will probably see more like those tips as the coco tries to find a balance.
Remember it could be that, or to me it looks like the start of deficiency or simply lack of food, you could try upping to 300ppm or stay a bit.....
Looks good though how is the poison doing?
Were just trying to help, I'm not one who cares if your grow situation looks like crap at the moment, same probably goes for the others here, were just seeing if we can help give you some advice on tweaks that might help so you can have a better more productive grow, cause to me half hearted grows, cause half hearted results.
Were all here for are own reasons but i say jump in, engage and have fun, and don't be embarrassed about what you currently have, as it takes time to dial in a space, we just have to be open to learning, that's my main reason for being here .
All set dude, you got roots showing, there is more in the cup, trust it. When did you take the cut? A while ago right, most likely it'd be toast by now if it wasn't taking.
Looking good man, keep it up!