Should I repot my blooming phal? Not much space left
 

I have a phal that just started blooming. The spikes have been developing for many weeks. Unfortunately, a few months ago I thought that I could keep it in the same pot for at least another 6 months or so until it finishes blooming. Now, it seems like that was a mistake. There are so many new roots that there are spots with barely any potting mix left. The roots have also occupied the bottom 1-2cm of the pot completely. There is also some algae growth now. I'm worried that repotting it will make it lose its buds, but I guess not repotting it would be even worse in the long run. I wanted to ask what you guys think I should do?

P.S I took the pics when the roots were dry cause otherwise it can be hard to see into the pot.

The medium still looks OK. The roots look great. You could repot now, or wait. I would wait.

I would also wait, the substrate still looks pretty good and the roots excellent. Most Phals are not picky and can be repotted in spike/bud/bloom without missing a beat, but there is a rather high risk of snapping off buds.

I wouldn't upsize too much when you repot, in my experience Phals really prefer being a bit rootbound. If that was my Phal I might even leave it in that size pot if I could get it back in without too much difficultly.

Substrate is more for moisture retention that anything else, and I've had a couple very rootbound Phals over the years that were amazingly happy and healthy, and without a single rotten root when I did repot.

Don't worry about the crowding, or the fact that some roots may escape from the medium. The plant looks great and conditions in the pot look fine. While Phals don't have a problem being repottied while blooming, there's always the risk of breaking a spike or knocking off buds while handling. Also, unopened buds tend to blast with any change of environment, If you really want to do it, you could gently lift it out of the pot and just drop into a larger one, adding some more bark - don't worry about removing the existing medium. That would minimize the handling. It were my plant, I'd leave it - wait at least until all buds are open if you really want to do it,