Have you ever vacuumed your tank and run out of water before you run out of crud? I could never seem to get my tank clean without removing most of the water. I looked at battery powered vacuums but the high prices and poor reviews made me reconsider.
I came up with this powered vacuum using old parts from past aquariums.
Step 1: Parts
The parts you need are:
An old powerhead (pump) with a magnetic impeller.
A regular gravel vacuum attachment.
Plastic tubing of various sizes.
Fine metal mesh, like window screen.
An old sock.
A rubber band.
Step 2: Fit Tubing to Powerhead
Find a piece of tubing that fits tightly around the inlet of the powerhead. Cut a piece one to two feet long. Find a size that fits over the outlet (probably not the same size) and cut a piece 3 inches long. The powerhead usually has a flow adjuster. I use the highest flow setting but a more powerful pump might need to be used at a lower setting.
Step 3: Fit Tubing to Gravel Vacuum
The gravel vac probably came with it's own tubing but if you don't want to cut the tubing, find another piece the same diameter. If the tube on the powerhead inlet is the same size as the one for your gravel vac you can skip the next part. If the tubes are not the same size, you can buy an adapter at the hardware store or you can slide one tube inside the other. Mine required three pieces of tubing (small, medium, and large) pushed together. This method is not as water tight as an adapter but the tubes will be inside the tank anyway.
Step 4: Make a Prefilter
I added a prefilter to catch the big chunks in the gravel vac. The small stuff doesn't hurt the powerhead but the bigger chunks will clog it up. I used an aluminum mesh that has fairly small holes and hold it's shape pretty well when formed into a dished shape. I placed the disc of mesh with the concave side facing the outlet hole so that the mesh was not pressed right against the hole. This provides more surface area to collect chunky stuff.
Step 5: Filter Sock.
I used an old sock that is fairly tighly knit sythetic material. You amy have to try a couple of different socks to find one that works best. Rinse it thoroughly before use to remove any detergent or fabric softener residue. Place the rubber band around the sock near the top. If you have a bigger rubber band, wrap it around a couple of times. Fold the sock down over the rubber band. Slide the sock covered rubber band over the outlet tube on the powerhead. If it doesn't stay in place, make the rubber band tighter.
Step 6: Vacuum
The powerhead won't work if air gets into it so carefully push the vacuum and tube into the water and get all of the air out of the hose. Then lower the powerhead into the water and connect the hose.
I like to keep a bucket with a couple of inches of water next to the tank. The prefilter will probably get dirty enough to reduce suction while you are cleaning. Pop the gravel vac off the hose and rinse in the bucket when it's too grungy.
When you're done vacuuming, discontect the hose and dump any accumulated sand from the hose back into the tank (if your tank has sand) and slip the sock off the outlet tube. Drain the power head and hose and store disconnected. This keeps the hose from stretching too much where it fits on the powerhead. Turn the sock inside out and rinse out the gunk.
It's still important to change the water in the tank. The vacuuming only removes the solid waste, not the build up of nitrates and other dissolved nutrients.