You are 100 percent sure.The floating ,,glass,, box helps a lot by keeping the light fixture clean so the light is not obstructed by dirt(calcium deposits) and it also isolates thermally the leds from the aquarium water.With the 5 mm led diodes i did an experiment and i didnt expected too much from them.The inspiration to use 5 mm diodes for the scrubber was when ive read about a member here that used blue 5 mm diodes to light his mainly acropora tank and it worked for a while.My next challenge is to build an algae scrubber for the cold water aquarium.For cold water and scrubber i dont have any experience and i dont know wich plants should i use,maybe il use ulva lettuce instead of GHA.In any case il keep the cold water aquarium as hot as the algae wants because i trust algae scrubbers and bacterial filtration works really bad in cold.