One thing I would do is to add an additional rock at the bottom and left of rock number 5 to help with the "base" of the main rock. It will extend more naturally. Among the rocks on the left they do look weird being piled up. None of them has the nice features as your main rock (no. 5), perhaps you can find 2 new pieces that can substitute for them. One bigger than No 2 and one about the size of No 3. Then use the bigger one to balance the right and the smaller one to balance the left. You will be left with a nice 5 pieces of rocks as well.
Just my 2 cents. Hope it helps.
Studying the water chemistry and nutrients is a science.
Knowing what plants to get and how to use them is an art.
Aquascaping is a marriage of art and science, the logical and emotional.
-Calvin
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