Hydor Koralia or Tunze for my 19G?

Love the tank btw, very clean looking. I like the rimless design. Is that a little bit of cyano I see on the sand bed?

 

GSP will tolerate intense lighting very well, unless you didnt acclimate it properly... i had mine about 6" below MH and it loved it... i would suspect high water temps are to blame... or just didnt acclimate them, maybe raise your lights a few inches and get a little clip on or computer fan to blow across the top of the water. guaranteed to get u into a comfortable temp... mine seem to thrive right at 80.5 deg F, they can tolerate temporary increases up to 90 deg F from what ive read but i think keeping them above 82 is no good... plus with the radiant heat from being close to the light the corals tissues are probably in the mid 90s