Magnet Cleaner Fish Tank Guide: Sizing and Use
This magnet cleaner fish tank guide helps Singapore aquarists pick the right magnetic algae scrubber for their glass thickness and avoid the scratch mistakes that ruin thousands of dollars of low-iron aquariums every year. Magnet cleaners are the single most time-saving maintenance tool in the hobby — a thirty-second weekly wipe keeps glass crystal-clear between water changes. At Gensou Aquascaping, 5 Everton Park, we sell and use Mag-Float magnets daily and have strong opinions on the sizing pitfalls.
How Magnet Cleaners Work
A magnet cleaner is a two-part device — an internal scrubbing pad with a magnet, and an external handle with a matching magnet and felt pad. You move the external piece along the outside glass and the internal scrubber follows, cleaning the inside algae film. No wet hands in the tank, no arm up to the elbow, no disturbing the aquascape.
Mag-Float as the Benchmark
Mag-Float from the US is the brand that defined the category and the default recommendation. Local distributor pricing at Qian Hu, East Ocean and C328 Clementi runs SGD 18 for the Mini (tanks up to 6 mm glass), SGD 32 for the Small (up to 10 mm), SGD 52 for the Medium and SGD 85 for the Large (up to 19 mm, for big display tanks). Mag-Float floats if it separates — you can retrieve it from the substrate without hassle.
Budget Alternatives
Hanako, Sunsun and Ista generic magnet cleaners at SGD 8-25 from Shopee work adequately for 4-6 mm glass tanks. Magnetic pull is weaker than Mag-Float so they drop sand onto the pad more often. Most do not float — retrieval means a hand in the tank. Fine for nano setups under SGD 300 total budget; upgrade to Mag-Float for anything over 60 cm.
Sizing to Glass Thickness
The number-one sizing mistake is picking a magnet rated for your glass thickness without checking that the pulling force matches. A Mag-Float Small technically works on 10 mm glass but struggles to hold firmly through it — the scrubber drops when you push harder. Always pick a magnet rated for one thickness tier above your actual glass. A 6 mm tank wants Mag-Float Small; a 10 mm tank wants Medium.
Tempered Versus Float Glass Warning
Most aquarium kit tanks have a tempered glass bottom — never use a magnet cleaner on the bottom pane. Grit trapped in the pad can scratch tempered glass, and the resulting weak point fails catastrophically. Side and front panels on most tanks are standard float glass and take magnet cleaners fine. When in doubt, check the tank manual.
The Substrate Line Problem
Sand grains and ADA Amazonia pellets are the magnet cleaner’s nemesis. A single trapped grain scratches a 30 cm line across a low-iron front pane in one careless pass. Keep the magnet at least 2 cm above the substrate line and switch to a finger-wiped algae pad for the lowest few centimetres. This discipline alone preserves contest-grade tank aesthetics.
Scrubbing Pads for Tough Algae
Green spot algae on older tanks resists magnet felt. Tunze Care Magnets and some Mag-Float models accept an optional abrasive pad attachment — use with caution, test first on a hidden corner. For stubborn algae, a plastic card scraper in-hand does a better job than trying to force a magnet. Blade scrapers on glass work but are risky for silicone seams.
Technique and Frequency
Weekly passes prevent algae from hardening. Diatoms and green film come off with a single gentle sweep; older green spot algae needs pressure and repeat passes. Move in slow overlapping lines from top to bottom, then horizontally — skipping patches leaves visible algae lines. Rinse the external pad under running water after use to remove any grit picked up from hands.
Float Versus Sink Features
Mag-Float’s floating internal piece is a killer feature — if the magnets separate mid-clean, the scrubber rises to the surface rather than sinking into your aquascape. Non-floating competitors (most cheap generics) land on substrate or plants, sometimes requiring a hand plunge into the tank. For any tank with fine-leaved foreground plants the floating design is worth the SGD 10 premium.
Saltwater-Specific Options
Flipper cleaners from the US at SGD 60-95 (imported via reef specialist Shopee sellers) have a flip-over feature that switches between a soft felt side and a stiff plastic scraper without taking the magnet out of the tank. Standard Mag-Float works fine in saltwater but struggles with coralline algae — the Flipper’s scraper side handles it. Worth the upgrade for reef keepers.
Storage and Pad Replacement
Store the magnet cleaner on a dedicated hook away from substrate so the felt stays grit-free. Replace felt pads every 6-12 months as they pack with algae spores and start to underperform. Mag-Float sells replacement pad kits at SGD 10-15; generic felt cut to size from craft shops (SGD 5 for enough to re-pad five times) is a working DIY.
Singapore Sourcing Summary
Qian Hu Pasir Ris, East Ocean Clementi and C328 Clementi carry the full Mag-Float range consistently. Polyart Aljunied stocks Tunze Care Magnets. Shopee local sellers handle Hanako, Sunsun and Ista generics plus occasional Flipper imports. Reef Point at Pasir Ris is the go-to for Flipper and saltwater-specific magnets. Always check the glass-thickness rating sticker before buying — no returns on opened magnets at most shops.
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Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
