Purchase Cerium Oxide from Vulcan's Work Shop on Ebay. Mix it with RODI water to make a paste similiar to pancake batter.
1. Turn off your pumps Lower your water level to the scratch.
2. Use Tape to lay a garbage back over your water On TOP of the water and tape it around the scratch.
3. Get a neon orange uv marker and circle the scratches. Turn on your actinics.
4. Load up a felt buffer pad with Cerium Oxide paste and kiss away 15 minutes of your life as you buff the area with the Cerium oxide mix while rotating in a circle and swearing like a pirate at the awkward angle, tank frame cutting into your armpit.. occasionally burning your self on your actinic bulbs..
for the first 6 minutes.. NOTHING WILL HAPPEN.
for the next 6-10 Minutes.. The Scratch will fade.. and start to look less and less..
Keep going and after a couple more minutes it should be 100% invisible when filled with water.
DO Tape well. Tape MORE.. Keep taping until you think nothing will get into your tank at At all.
Corals should be fine out of water for a while.. if your like me... Drain your tank half way into a rubber maid bin and pry off the plugs that corls were on in the top half of my tank and placed them into the rubber maid with a heater and maxijet.
DONT
Hold the buffer/dremel in 1 place too long.
Use dry powder.
Inhale the Powder
Sell the Powder on the corner
Use the powder for world domination
Cerium Oxide is inert. If some gets into your tank it should not do anything. Cerium oxide is sometimes sold as diamond powder. Get the purest cerium oxide you can find. It might sound daunting but repeated treatments of cerium oxide can remove most scratches.. including the dredded can feel with finger nail scratch