I just bought some discus and I'm considering using a UV unit on that tank, also to use it as a tool for GW when it rears its ugly fog in my other tanks.

Anyway, I heard (long ago) that UV units fry trace elements/Micro nutrients. Is that true? Anything else to worry about in the use of them in planted tanks?

I was going to buy a Turbo Twist 3X 9 watt. Is that a good one for a 46g (discus tank) and occasional use on a 75g for GW?

thanks,

Russ