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Seachem Tidal 75: What to Know
The Tidal 75 sits in the middle of Seachem's Tidal power-filter line (35/55/75/110), and at the 75 size it's rated by Seachem's own spec sheet at 350 US GPH for tanks up to 75 US gallons (300 liters). What separates the Tidal line from a typical HOB filter is the extra engineering Seachem put into day-to-day maintenance: a built-in maintenance monitor that gives you a visual cue when flow has dropped enough that it's time to clean the media, an adjustable flow control so you're not stuck with one speed, and a self-cleaning, corrosion-resistant impeller that Seachem states is suited for both freshwater and saltwater use.
The media basket is large and set up to take mechanical filtration (the included foam) and biological filtration (Seachem's own Matrix bio-media, sold separately or in some bundle listings) in the same basket, with room to add chemical media like carbon if you want it — it's not a rigid three-chamber layout like the canister filters in this guide, but a single large customizable basket. It also has a surface-skimmer inlet, which pulls water from the top of the tank to clear the oily film that can build up on the surface and block gas exchange, a detail a lot of cheaper HOB filters skip.
Setup is plug-and-clip, no plumbing, consistent with every hang-on-back filter in this guide, and Seachem's own materials describe installation as fast. At its price it's arguably the most feature-dense HOB here — the maintenance monitor and adjustable flow are things you'd otherwise pay canister-filter prices for.
Key Listed Features
350 US GPH flow rate, rated for tanks up to 75 US gallons (300 L) per Seachem
Adjustable flow control and built-in maintenance-due monitor
Self-cleaning, corrosion-resistant impeller rated for fresh and saltwater
Surface-skimmer inlet plus a large customizable mechanical/biological/chemical media basket
