method:
1. empty all substrate + decor from the tank
2. wipe out the bottom + sides of tank with damp rags
3. using 1st razor blade scrape off as much old silicone as possible
4. dispose of all old silicone into trash
5. damp rag with vinegar and wipe along edges of tank where old silicone was
6. using 2nd razor blade, scrape off all other silicone left in the tank
7. use damp rag and wipe out the inside of the tank
8. use the new silicone and apply, making sure that the tip is pushing against the silicone to create an air tight seal; put extra silicone in the corners
9. use your finger to create an arch in the wet silicone against the edges of the glass
10. use a damp rag to clean up excess silicone
11. let silicone cure for 24 more hours than it says on the silicone bottle
12. fill up tank with water without putting any of the substrate or decor back into the tank
13. wait 1-2 weeks and if there is still no leak then it is probably safe to set up