I think you may have pulled the trigger but shot a blank.
What I mean by that is in my opinion one of the reasons loaches are more difficult to spawn is they require more specific triggers to breed than say corydoras catfish. That said, the night before you did a 25% water change and changed your lighting. Perhaps that combination of change started your loach, and, or loaches to commence initial spawning behavior. They didn't spawn so you didn't make all the right moves to initiate it, but it's possible you are on to something. Of course, then again, it might not have meant a thing.
Just for the heck of it you might want to try changing your bulbs back, feeding them a LOT of fish eggs and then replacing your bulb again while doing a water change. It would be interesting if the excessive swimming behaviour again happened and maybe more cool stuff might follow. Then again, it might be a complete waste of your time and you might curse me out for being a nutcase.
