Hi Victor,
Coralline growth could eventually become a factor if left unchecked over an extremely long period of time.
Good maintenance practice on any reef system dictates cleaning of all devices on a regular basis. In this case it may be once or twice a year.
At present the clearances are sufficient to cater for some growth.
I will attempt to build all submerged components in black pvc as this seems to become less encrusted than other types over time.
IMHO, with the constant motion that this device exhibits, any build-up will be very gradual.
Thankyou for the observation, it is a valid point.
