If you have a gravity based siphon and have not used one many people have trouble at first. It is really quite simple to get the flow going. Have the bucket ready in front of the tank, place the entire siphon into the tank, take the fat end and push it down and allow the end to tip upward. It will fill with water. Stretch out the rest of the line so the air bubbles move up the hose toward the small end. When you have worked out all the bubbles and the hose is completely full of water and no air pockets place your thumb over or crimp the small end of the tube with one hand. Use the other hand to make sure the wide end stays completely submerged (they want to pop up sometimes). Pull out the small end (keeping it closed off or plugged) and place it in the bucket on the floor in front of the tank. Remove your finger or release the crimp. Water should flow. You have made a siphon. When the bucket gets full plug the end like before and replace it into the tank under water so you can dump your bucket. I love to use the fish tank water on my plants in the summer months. Otherwise I like to dump the bucket into the toilet rather than sinks to avoid clogs in drains or damage to garbage disposals from any sand or gravel. If you have a newer automatic faucet siphon you should assemble it as directed on the packaging and hook to faucet. The part on the faucet has a knob on the bottom that when turned one way makes water flow in and turn it the other way and water flows out of tank. Both use your running tap to increase flow rates. One important fact on faucet siphons is they have a shut off valve near the siphon end, this should not be shut for a long time when the water is flowing in it. This can cause a build up of pressure. That said, siphon the same as I described below for gravity siphons.

To vacuum gravel:
Now you will need to lightly press the wide end into the gravel about an inch or so and you will see a small amount of gravel start swirling in the tube and a bunch of gunk come up from underneath. When it runs clearer move the end to a new area. If the gravel gets stuck simply lightly tap it on the glass or rocks to dislodge the gravel. Go around decorations very good and the back and front edges and down the center area if it’s open.

To vacuum sand:
Sand is often thought to be harder to clean. I have sand and find it much easier to vacuum than gravel because the debris stays on the surface of the sand rather than going into the rocks and gravel. The key to vacuuming sand is to lightly run the siphon over the top of the sand, barely touching the surface. You do not want to jam the end of the siphon into the sand as you would gravel. Gravel is fine and will all come up into the siphon. If this occurs tap it like I described for the gravel. You can clean much more of the sand in the same amount of time as you had for gravel. It is easier once you get the hang of it.

Replace the water:
Replace water removed with dechlorinated water. You can use a common dechlorinator or water conditioner. If you use water conditioners, be sure to mix them in a half bucket of water as many are thick now with aloe, other items and can coat the gills of any fish that come to the surface or swim into the stream.

Wipe or scrape the algae:
If you have algae on the glass wipe it away with a green scrub pad commonly used in kitchens (make sure its plain with no soap on it). You can also use magnet cleaners commonly sold in almost every hobby store. If the algae will not come off then you can take a razor blade and carefully scrape it off. Be careful around the corners where the silicone seals the seams. Make sure you do not forget the glass canopy, the underside near the light strip will often have algae and hard water marks, you must be sure to clean it properly. Sometimes decorations can get out of hand with algae its often better to just replace the decorations in the tank.

To clean or replace filter cartridges:
You can extend the life of the cartridges if you rinse them out once a week in a half bucket of tank water. Swish it back and forth and lightly rub any thicker areas . Then replace in the filter. If it is extremely dirty or older this is the time to replace it. The flossy pouch that holds the frame will thin over time and when this occurs it is time to replace them.

Check the hardware:
Make sure when changing your water you unplug your heater so that it does not shatter on you, this can often happen when a heater is no longer submerged in water. When this is done it is a good idea to check the filter and heater and lighting cords for any wear and tear and make sure all looks good and is correctly placed in the tank.

Clean the glass outside using vinegar:
Now that the inside of the tank is clean its a good idea to wipe off any streaks or watermarks on the outside. I like to use vinegar on a clean paper towel. It smells funny at first but is superior for cleaning and does not leave streaks. Best of all it is not ammonia based like other glass cleaners and will not harm the fish. I place some vinegar on a wad of paper towels and wipe the glass, drying with a dry paper towel as I go. To dry the glass newspaper is also an effective wiping material that will not leave streaks. I start by doing the three exposed sides and then the glass canopy tops. By this time the water should have cleared and I like to inspect my fish for injuries or diseases.

Now your tank is clean and free of debris, and the fish have had a water change. Sit back and enjoy your beautiful fish.