Hey pls read up more on which lighting to have in order to keep certain coral or invertebrate......
Do you know that hammer and bubble need moderate to strong lighting to thrive.... IMO your 18watt FL is no way for even the lowest light demanding coral such as mushroom............. IMO minimum a Pl light is then sufficient to have those coral....
And also pls note that anemone and maxima clam need very strong lighting to thrive such as metal halide........ And they can no way be kept under 18watt of FL.....
Pls show us some pic of what you describe as doing ok coral and invertebrates ...... Because they have just gotten yourself some very light demanding invertebrates and corals.................
Sorry for my harsh tone as i really wan the live stock to thrive in your tank