For those of you keeping mbuna who have loads of rock from glass-to-glass in your tank (either front to back, end to end, or both), you know how difficult it is to vacuum the substrate around the rocks using a standard Python. Though rock work still needs to be removed and the substrate vacuumed on a regular basis, you don't have to do it every water change, especially if you do water changes at least weekly. In fact, I would recommend that you don't. However, there are several ways to vacuum some of the crevices and tight spaces without moving the rock.
You can always employ the old gravity siphon method by simply using just a small diameter hose. A better solution and one that works quite well is to cut a short piece of PEX pipe and attach it to the small diameter hose. The PEX is flexible but not near as much as the hose itself and it provides just enough rigidity to poke into tight spots without having to grasp it near the end like you would using just the hose end alone. You can also modify your python so that it "steps down" in diameter to a much smaller size and then attach the PEX at the end. This will essentially turn your Python into a super vacuum with significant suction, if you run the faucet while vacuuming!
In the above photo, I've cut a 6" length of 1/4" PEX which I've inserted into a 1/2" OD hose. You should be able to find PEX pipe at your local hardware store. I got mine at Lowe's. I've used a zip tie to keep the hose from sliding on the pipe because, though the fit is pretty good, it's not as tight as I would like. In addition to getting into tight spaces, this works really well when you're trying to do some real precision vacuuming, especially around shell dwellers with really small fry. I haven't modified my Pythons to step-down to the small diameter. I'm using it with the standard gravity siphon because I have sand substrate and the gravity suction is just enough.
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