Matala BioSteps-II Filter with 16W UV – Pond Filter for Ponds up to 2,000 Gallons

⚠ FILTER + UV UNIT ONLY — Pump and Tubing Sold Separately The Matala BioSteps-II Filter with 16W UV Clarifier (SKU 99978) is the gravity-fed filter body and UV clarifier unit — without a pump or tubing. It combines Matala’s 6-mat progressive density biological filtration with an integrated 16W EZClear UV clarifier that eliminates free-floating algae (green water) before it can cloud the pond. Designed for water garden ponds up to 2,700 gallons (or koi ponds up to 1,350 gallons), it accepts pumps delivering up to 1,060 GPH with an ideal operating flow of 800–900 GPH. ⚠ Pump required — not included. The BioSteps-II 16W UV (SKU 99978) is the filter and UV unit only. You will need to supply a submersible pump rated to deliver 800–1,060 GPH at your installation head height, plus connecting tubing. For a complete kit with pump, tubing, and waterfall spillway included, see the BioSteps Plus W Kit (SKU 31351). 2,700 Gal (WG) / 1,350 Gal (Koi) Max 1,060 GPH Ideal 800–900 GPH 16W EZClear UV (Philips T5) 6 Matala Mats (3 Densities) 200 sq ft Surface Area 20”L × 15”W × 23”H Key Features & Benefits ☀️ 16W UV Clarifier — Eliminates Green Water The integrated 16W EZClear UV clarifier uses a Philips T5 UV lamp to destroy free-floating algae cells as water passes through. Green water (suspended algae blooms) is eliminated at the UV stage before reaching the filter mats, dramatically improving water clarity. 🪜 Progressive Density Filtration Six Matala mats in ascending density — 2 Green (coarse) → 2 Blue (medium) → 2 Gray (fine) — capture progressively finer particles in a staircase sequence, protecting the biological media and maximizing mechanical efficiency. 🧬 200 sq ft Biological Surface Area The BioSteps-II provides 200 square feet of colonizable surface area for nitrifying bacteria — bacteria that convert toxic ammonia into safer compounds. This biological capacity is the core water quality mechanism for fish health. 🔀 Cross-Flow Design Water enters from the side and exits at a different angle via the cross-flow pattern, trapping more debris at higher flow rates without plugging. If media becomes heavily clogged, the internal overflow bypass routes water safely to prevent pond drain-down. 💡 UV Verification Window The UV unit includes a clear threaded cap that lets you visually verify the UV lamp is illuminated without disassembly — so you always know the clarifier is actively working without opening the filter. 🧹 Easy Backwash Cleaning The sloped tank bottom channels settled solids toward the drain plug for backwash cleaning. An optional drain valve (sold separately) enables plumbed backwash without any disassembly. The UV unit mounts inside the filter housing — no additional plumbing required. Technical Specifications Specification Value SKU / MPN 99978 / BSTPII-16W Product Type Filter + UV Unit Only (pump and tubing not included) Max Pond Size (Water Garden) Up to 2,700 gallons Max Pond Size (Koi Pond) Up to 1,350 gallons Max Pump Flow (through filter) 1,060 GPH Filter Operating Flow (ideal) 800–900 GPH UV Clarifier 16W EZClear — Philips T5 UV lamp UV Lamp Life 9,000 hours (annual replacement recommended) UV Ballast Electronic ballast, tuned to 16W lamp UV Verification Clear threaded cap for visual lamp confirmation Filter Mats 6 Matala mats: 2 Green (coarse) + 2 Blue (medium) + 2 Gray (fine) Biological Surface Area 200 sq ft Dimensions (L × W × H) 20” × 15” × 23” Inlet Fitting Swivel with barbs: 3/4”, 1”, 1-1/4”, 1-1/2” Outlet Fitting 1.5” or 2” gravity return Drain Sloped bottom + sludge drain plug; optional drain valve sold separately Flow Design Cross-flow with overflow bypass safety feature Tank Material Automotive grade plastic Optional Upgrades Waterfall Spillway (sold separately) | Drain valve (sold separately) Pump sizing guidance: Your pump must deliver 800–1,060 GPH at your installation head height. Do NOT use a pump rated above 1,060 GPH — overdriving the filter reduces biological contact time and UV exposure time, degrading both filtration and clarity. Call us at (765) 508-4352 for pump selection help specific to your installation. Frequently Asked Questions What is the maximum pond size for the Matala BioSteps-II with 16W UV? The Matala BioSteps-II Filter with 16W UV Clarifier (SKU 99978 / MPN BSTPII-16W) is rated for water garden ponds up to 2,700 gallons. For koi ponds with higher biological waste loads, the recommended maximum is 1,350 gallons to maintain adequate nitrification and water clarity. The filter handles pumps delivering up to 1,060 GPH at your installation head height. This listing is for the filter and UV unit only — a pump and connecting tubing are required and must be purchased separately. For a complete kit with pump, tubing, and waterfall spillway included, see our BioSteps Plus W Kit (SKU 31351). How does the Progressive Density filtration in the BioSteps-II work? The BioSteps-II contains six Matala filter mats in three densities, arranged in a staircase sequence: 2 Green mats (coarse) — capture large solids (leaves, algae clumps, debris) first, protecting the finer mats from premature clogging 2 Blue mats (medium) — capture medium-size particles; primary biological colonization zone 2 Gray mats (fine) — fine mechanical filtration and maximum surface area for beneficial bacteria; highest density stage The six mats together provide over 200 square feet of surface area for nitrifying bacteria. The cross-flow design directs water through each stage without channeling, ensuring maximum contact time even at higher flow rates. What is the recommended flow rate for the 16W UV Clarifier? To achieve crystal-clear water, a flow rate of 800 to 900 GPH through the filter is the design target — this provides sufficient UV contact time for the 16W Philips T5 lamp to destroy free-floating algae cells. The absolute maximum pump flow through the system is 1,060 GPH. Do not exceed 1,060 GPH with your pump. Faster flow reduces both UV exposure time and biological contact time in the filter, significantly reducing water quality outcomes. The UV lamp is rated for 9,000 hours — Matala recommends replacing it annually even before it burns out, as UV output degrades before the lamp visually fails. The clear threaded cap on the UV unit lets you confirm the lamp is illuminated at any time without disassembly. How often should I clean the BioSteps-II filter mats? Clean the filter mats only when flow becomes noticeably restricted — not on a fixed calendar schedule. When cleaning: Rinse the mats in a bucket of pond water (never chlorinated tap water — chlorine kills the beneficial bacteria living in the mats) A gentle shake or pour of pond water over the mat is usually sufficient to dislodge trapped debris Open the sludge drain plug at the base of the filter to remove settled waste before and after mat cleaning Rinse one section of mats at a time to preserve as much bacterial colony as possible Does the BioSteps-II include an overflow safety feature? Yes. The BioSteps-II uses a cross-flow design that inherently prevents the clogging failure mode seen in traditional down-flow filters. If media becomes heavily blocked by excessive debris, water internally bypasses the clogged sections to maintain flow — preventing your pump from pulling the pond level down to the filter inlet. This overflow safety mechanism is built into the cross-flow geometry of the housing rather than being a separate mechanical valve. What size tubing is compatible with the swivel inlet fitting? The swivel inlet fitting accepts 3/4”, 1”, 1-1/4”, and 1-1/2” flexible tubing via integral barbs. The outlet is a 1.5” or 2” gravity return connection, allowing connection to the pond edge or an optional waterfall spillway (sold separately). The filter returns water to the pond by gravity — no pressure is required at the outlet side. Why Buy from Pond Pro Direct? Authentic Matala products with full manufacturer support Expert pond sizing and pump selection — call or text (765) 508-4352, Mon–Fri 9am–5pm EST Free shipping on all orders Price match guarantee on identical products 30-day return period on eligible items