Do I need different fish tank cleaners for glass and acrylic tanks?
Yes. Acrylic scratches easily, so you'll want non-abrasive pads, plastic blades, and magnetic cleaners with soft pads. Skip metal blades or rough scrubbers. For glass, you can use stiffer scrapers and stronger magnets, but always check that the tool is labeled for your tank's material to avoid damage.
How do I vacuum a sand-bottom aquarium without removing the sand?
You can use a vacuum with adjustable flow or a narrow intake and hold the tube just above the sand. This will help you lift debris without pulling up the substrate. Pinching the hose will reduce suction, and adding a prefilter sponge or intake guard will catch fine particles. Work in small areas when you do partial water changes.