Its EXTREMELY hard to keep tanks that small as a new reefer. Too much can go wrong way too quickly. And if your not home all day its hard to keep it stable. Try to put the lights on when you get home instead of them being on when your not there, its going to help you control the tank. And clean out that algae, its unwanted and only causes more problems with corals.
While I don't disagree with tosiek, I understand where you're coming from - you're new to the hobby, live in a small space in the city, and you're not quite ready to put down a wad of cash for a 50 gallon tank. You're probably not even sure how ready you are to commit to this hobby in the long run - it's not a cheap or easy one.
While keeping a nano tank can be a bit tricky, it's certainly not impossible if you're vigilant. My first tank was an Eclipse 6, and I had it for 10 months before I broke it down (I had to move) - the only time that I really lost livestock was in my previously mentioned heating disaster. It's true that parameters can swing pretty drastically in a tank this small - I think that I had days where there was a temperature differential of four degrees between noon and midnight. Unfortunately, this can't really be helped unless you (a) have a larger tank, and (b) have some system to keep temperature stable, such as a controller that governs heating (heater) and cooling (a fan or a chiller).
Ultimately, this tank is only going to support the hardiest of corals in the long run - mushrooms, zoas, star polyps, etc. I would say that kenya trees are in this category, so don't give up. Do what everyone has suggested so far - change your photoperiod so that you can monitor temperature more closely, test your phosphates, expand your cleanup crew, get rid of all your excess algae by hand, and continue to do regular water changes. Hopefully you'll eventually get your tank to a place where everything is happy!