The core of the correct use of silicone glue for fish tanks is "clean base material + standardized gluing + full curing". It is necessary to avoid oil and moisture from affecting the bonding during the entire process, and at the same time control the thickness of the glue layer and the curing environment. The specific steps and key points are as follows: 1. Pre-construction preparation (the core that determines the bonding sealing) Substrate treatment: The glass surface needs to be wiped with alcohol or isopropyl alcohol to remove oil, dust and moisture, and ensure it is completely dry (no residual water stains or fingerprints).  If you are repairing an old fish tank, you need to use a blade to scrape off the original aging glue layer, and then use sandpaper to lightly grind the joints to enhance the adhesion of the new glue.  Tools and environment preparation: Tools: glass glue gun, utility knife (glue cutting nozzle), scraper (or gloved fingers), textured paper (optional, used to assist shaping).  Environment: The temperature is controlled at 5℃-40℃, and the humidity is 50%-70% optimal; maintain ventilation (especially acidic glue, which needs to dissipate odor), and avoid dusty environments.  Glue nozzle treatment: Use a utility knife to cut the glue nozzle at an angle of 45°. The diameter of the cut is adjusted according to the width of the joint (usually 1-2mm, which is slightly smaller than the width of the joint to ensure a full glue layer).  Load the glue gun and squeeze out a small amount of front-end colloid (may be mixed with air) until the colloid is even and bubble-free before starting construction.  2. Gluing and shaping steps (make sure the glue layer is even and without gaps) Apply glue evenly: Hold the glue gun, keep the glue nozzle and the glass seam at a 45° angle, advance the glue gun at a constant speed, let the glue completely fill the joint, and avoid glue breaks and bubbles.  Structural bonding (such as fish tank splicing) must ensure that the glue layer thickness is ≥1mm, and the glue completely covers the glass edges on both sides of the joint (each extends 2-3mm).  Shaping and trimming: Immediately after gluing, use a scraper or gloved fingers (dip a small amount of soapy water to avoid sticking to your hands), and scrape the glue along the direction of the seam at one time to form a smooth semicircular or triangular glue surface (to enhance sealing and aesthetics).  If you need precise shaping, you can first stick masking paper on both sides of the seam, scrape it off and tear it off immediately to avoid adhesion after the glue solidifies.  Check the glue: Observe whether there are bubbles, gaps or unfilled parts in the glue layer. Use a glue gun to fill the glue and then scrape it flat again to make sure there are no omissions.  3. Curing and post-processing (the key is to "rest patiently") Initial curing: The acid glue will dry for about 10-30 minutes, and the neutral glue will dry for about 30-60 minutes. During this period, avoid touching the glue layer, moving the fish tank, and keeping away from water.  Keep the environment ventilated. Acidic glue needs to be ventilated for more than 24 hours to dissipate the acetic acid smell. Neutral glue needs to be ventilated for 12 hours.  Complete curing: Small fish tanks (≤50cm) need to stand for more than 48 hours, medium and large fish tanks (>50cm) or structural bonding need to stand for 72 hours to ensure that the colloid is completely cured (the curing speed is affected by temperature and humidity, low temperature and low humidity require longer time).  Water injection test: After curing, first inject 1/3 of the water and let it sit for 24 hours to observe whether there is leakage; if there is no leakage, then fill it with water and continue to observe for 48 hours. Make sure the seal is good before adding fish and shrimp.  4. Key points for avoiding pits: It is prohibited to use ordinary construction glass glue instead of special glue for fish tanks to avoid harmful components contaminating water quality.  During construction, the adhesive layer should not be too thin (<1mm), otherwise it will easily crack under water pressure; nor should it be too thick (>3mm), which will prolong the curing time and easily generate bubbles.  During the curing period, avoid direct sunlight or close to heat sources to prevent the adhesive layer from aging and shrinking.  If the glue cracks or falls off after curing, it is mostly because the base material has not been cleaned or the curing time is insufficient. The old glue needs to be completely removed before re-construction.