When you say from green to clear green, you mean losing color, going translucent, or bleaching?
It could be stressed from the change in lighting. As a general rule I give most new additions some time to acclimate to my lighting.
Bleaching can happen for various reasons though. Not all just from lighting.
That's one of the difficult things about coral. The manifestation of the symptoms can be the same or similar for a range of problems.
As for the alk test, I got a Hannah checker a while back that I love. It was about $60 and is really easy to use.
I've also used the seachem alk test, both the normal one that comes with a pH kit and the fancy one that does carbonate alkalinity. They both did well for me. Although the simple one drifted over time to be fairly inaccurate. That happens when reagents get old though. Nice thing about it is that they included a reference sample, so I always have a known quantity to gauge it against.
Salifert is also supposed to be a good brand of test kits.
I would stay away from API and strip tests. I've had nothing but issues with them.