Nice little reef in the making you have there! We can see the coraline algae blooming which is a very good sign.
I haven´t kept reef tanks for more than 5 years (after 21 years with reefs I needed a break, so now I only have FW) but from what I still remember I would give you a couple of hints:
- I have kept several mandarins and it is very complicated to keep them in the long run in a small tank. They need to eat tons of copepods to thrive and for that you need lots of stable (old) live rock. Around 10-15kgs (22-35 pounds more a less) per fish. Wihout constantly eating copepods, they become weeker and weeker and eventually die in a few months. Furthermore with the 2 "stenopus" shrimps (sorry but I dont´t know the English name) competing withthe mandarin... the odds are not good;
- another difficult combo is the tomato clown (very hardy and aggressive for its size) with the young "premnas" clowns (again... don´t know the English names). Once they´re older and bigger they´re very hardy also, but when young.. .it´s not the case.
Just my 2 cents. Enjoy your reef