That is very true. In certain situations such as using zeovit or when adding your own water born bacteria/micro organisms then you wouldn't want to use a UV unit.
okay i think i may leave that and put money towards the live rock and an mp40w es. because if i ever needed to quarenteen a fish i could just use copper treatment anyway yes?
I take what you are saying as an it not essential so not part of my get up and running costs.