resurrecting this, exactly what I was researching, in past tanks I have I tried external canister filters with the input hose used directly as a vacuum or with a wider mouth gravel cleaning attachment on it, and it worked great for some time but would inevitably have problems with clogged input, that reduces the suction from canister, either some clump of algae or a pebble gets pulled up and wedged in tube or in the pump intake inside the canister head, and un-clogging that just once would pretty much wipe out any gains made by using it in the first place in terms of time and clean-up.
Instead I'm using a small cheap HoB filter, and just remove everything from the filter chambers and stuff some medium or large sized cell foam as media into the filter reservoir. I temporarily hang it on display tank, turn off skimmer, keep flow pumps on, turn HoB on, and then I clean/scrape algae with brushes in the tank, and stir up the top of sand bed, this kicks all the detritus into the water column. I have the flow pumps turned on in the display tank to keep it suspended and moving, and I'm able to leave it alone and run an hour, afterwards, the water is mostly clear, as most of the junk is now stuck on the filter media in the HoB, but still nutrient/solids heavy and can't run the skimmer yet as it will just overflow, so I stop the HoB and let the flow pumps run another hour at about which time the dissolved stuff in water has thinned out and able to turn skimmer on.
Sometimes, I'll polish the water further by taking out the medium cell sponge media from the HoB, which is just caked in junk, and putting in a carbon coated filter pad like from Acurel, which has similar fine grained weave as a filter sock, and let that run for 30 minutes, after which the water is sparkling and can turn on the skimmer.
In all cases, at the end, I turn off the HoB filter, take it off tank, dump water left in its reservoir back into aquarium and throw out the filter media as it's just caked with all the crud and am done. No water on floor, hoses with water in them, priming, etc. I put the HoB in storage and take it out whenever next cleaning session needed. For nano tanks, like the 16gal I'm currently running, it's ideal as it doesn't result in any real water volume change, which I don't want as I'm not trying to accomplish a mass water change or replacement during this cleaning, I just want to remove algae and crud. I use an automatic water changer based on a recurring doser pump schedule, so, I the system never has a single, large water change event under any situation, which can be harsh on smaller volume systems.
