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That screen has one 15 watt bulb ?

It is too focused for the screen size, yes. Need to be spread out more, but, as the screen fills in, it might be ok.

Try putting a 1" circle of cloth on the glass in the middle, to shade it for a...

That's where the light is closest.

Heat sink should not get too hot.

Here are some lights:
http://algaescrubber.net/forums/showthread.php?2884-red-blue-led-grow-bulb&p=36256&viewfull=1#post36256

Welcome from the UK.

Bubbles look good. The light is white?