Help me save this baby orchid please
 

Hello beautiful people. The other day I was watering like normal my orchids and this one got some water on the crown (happens) and when I went to remove it I was stupid enough to somehow apply enough force to literally snap the new tiny leaf that was growing... Some days later and now the orchid is starting to have a yellowing leaf and I am worried this could now kill my orchid. So I was looking for some advice on how to proceed.

The orchid is potted in a sphagnum, bark and perlite mix, the roots look green and healthy and I fertilize with about 70-100 ppm of N on each watering. I also just applied some Kelpak for some more root growth.

Thanks a lot for reading all this, below I attach a pic of the said orchid

I can't remember your growing conditions. Temperatures day/night? Humidity? How do you decide when to water?

My temperature stays mostly consistent at 22-27 during the day and drops to about 20 at night. My humidity usually stays between 45-60% and I water when I see the roots start to silver and the media starts to feel really dry (easy to notice because of the sphagnum).

I can't look up its ancestry on Orchid Roots right now. It's been down for a few days. But photos show it probably has a lot of ancestors - like Phal. gigantea - that want high humidity and high temperatures, all the time. Such plants carry fewer leaves in cool homes than in ideal conditions.

I would suggest finding a way to raise the relative humidity to 60% and higher, and give more heat.

It's a good idea to look up the ancestry of plants before buying. This kind of Phal. is not easy to grow well in most homes.

I see, yeah it has phal. gigantea as the pollen parent. I tried with this one to add more sphagnum moss so that it can have a bit more of humidity.

Is there anything I could do right now to help it apart from the increased humidity? It just seems so weird to me that it suddenly started to yellow 2 days after I snapped the new little leaf because it had been doing just fine for like 3 weeks. Could it somehow have some rot in the stem and that caused the new leaf to snap so easily? Although I remember that when I snapped it it was all green and fresh but everything came off and no leftovers were left on the plant so that kinda surprised me.

What is the composition of the medium?

It's equal parts of bark and Sphagnum moss and then like 15-20% perlite

My intuition tells me that you should take the sphagnum out.

I see, I checked the roots and they all look really green and healthy there is 0 rotting so you think they could soon start to rot because of the media? I always let it dry out between waterings but I know that in the Spanish summers I'll have to water every 2 days so I wanted to prevent it a bit since I won't always have time

Perlite and sphagnum are water retentive. With that propotion (50 %) it might be suffocating the roots (they need humid air around them).
I would keep the perlite and reduce the sphagnum to 20%. I would also increase the bark size as it seems to be too small.
I don't know where you live in Spain but my summers have hot temps and day humidity often as low as 15%. I use only coarse bark or a mix of bark+LECA +Perlite or coco chips and the plants can handle it very well. The "secret" in this environment is to increase watering.