hi bro...here are some points you need to take note off..
1) the pic u posted abt your sump, i realise that u place those coral chips at both the gaps, take note that by doing this, it will restrict the flow and corals chips are not recommended because it will discharge sand that will cause nitrate probs n follow by phosphate. u can replace it with sinter glass rings but again i suggest not to place your filter media in between the gaps.
2)i believe your tank thickess is 6-8mm, be extra careful when you add in more rocks or corals, doing maintenance must be slow n steady because im afraid the tank will crack and it will be a nightmare.
3)since u are using a BK skimmer, plus a no. of pumps running, ur tank temp will naturally shoot up to above 30...lots of fishes cannot tolerate.
4)ur first picture also shows that ur sandbed is quite dirty, y not u go bare bottom or u can spend a great time siphoning those dirt out of ur sand, it will lead to bad water parameters and lastly, in future if u decide to keep corals, ur rockscape will have to improve on it...the current corals cannot accomodate the maximum number of corals u wish to hav in ur tank...
also, please state wad kind of return pump are u using..
hope my inputs will help u to improve in the near future..