Sps growth pattern

[Jon M.]

I have two sps corals that are plating on the rock and not going up. Why is this? One is a german blue digitata and the other is some green thick fingered coral.

 

[Reefpuck]

Could be flow.

 

[hatfielj]

Monti's exposed to lower light levels tend to grow outward more. The ones exposed to higher light tend to "twirl" upwards. Corallabs discovered this in their experiments with different light settings.
Flow can also alter this.

 

[Jaysushi]

I agree with both answers above, and some acros will encrust to establish a stronger base if the flow tends to be high. Not always the case though.