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Matala Spectrum — polished stainless UV-C for serious koi ponds
A mirror-polished stainless reactor reflects UV back through the water instead of absorbing it, so every watt works harder. Rated to 125 psi for pressurized systems, with Philips T5 lamps, quartz sleeves and full-range electronic ballasts. Four wattages up to the four-lamp 300 W with 3" ports; each is available with or without unions.
- Housing
- Polished stainless, 125 psi
- Lamps
- Philips T5 × 1–4
- Flow (peak)
- 4,000–17,000 GPH
- Ports
- 2" (40–150 W) · 3" (300 W)
- Lamp life
- 9,000 h
Image coming soon
Mystic Koi’s take
This is the UV we run on our own systems. For a stocked koi pond, size at about 20 W per 1,000 gal and keep flow near one turnover per hour, never above Matala’s peak flow — dwell time is what kills algae. Buy the "U" model: unions let you pull the unit for lamp changes without cutting pipe.
What it does
- Stainless reflectionPolished chamber boosts effective dose.
- 125 psiSafe on pressurized filter returns.
- Full-range ballast100–240 V electronic ballast.
- Philips T5 lampsHE 40 W or HO 75 W; 150 W uses two, 300 W four.
- 2" / 3" portsMatches big pumps without necking down.
- ServiceableLamps, sleeves, ballasts, O-rings and unions all stocked.
Sizing & flow
| Model | UV-C | Max flow (GPH) | Matala max pond | MK garden (10 W/1,000 gal) | MK koi (20 W/1,000 gal) | Ports |
|---|---|---|---|---|---|---|
| SS-L40W / WU | 40 W | 3,500 / 4,000 | 6,000 / 7,000 gal | 4,000 gal | 2,000 gal | 1½" / 2" |
| SS-L75W / WU | 75 W | 5,000 / 5,700 | 10,000 / 11,500 gal | 7,500 gal | 3,750 gal | 2" |
| SS-L150W / WU | 150 W (2 × 75) | 6,500 | 13,000 gal | 13,000 gal | 7,500 gal | 3" |
| SS-L300W / WU | 300 W (4 × 75) | 17,000 | 30,000 gal | 30,000 gal | 15,000 gal | 3" |
Manufacturer rating vs. our recommendation: Mystic Koi figures are our experience with heavily stocked koi ponds in warm US climates and are never shown above Matala’s rating. Flow rate is the make-or-break spec — stay under the max GPH.
Pairs well with
The science: how UV-C clears green water (and what it can’t do)
Free-floating single-cell algae turn pond water green. UV-C light at 254 nm damages their DNA as they pass the lamp, so they clump and get trapped by the mechanical filter. Dose = intensity × contact time, which is why flow rate matters as much as wattage: push water past the lamp too fast and the dose drops. Koi ponds carry far more nutrients than water gardens, so Matala rates koi ponds at roughly half the gallons of a general pond. UV-C does not touch string algae on the walls or replace biological filtration.
- Matala Water Technology Co. (2026). EzClear, Immersion and Spectrum UV-C clarifier data sheets. matala.com.tw.
- Hijnen, W.A.M., Beerendonk, E.F., Medema, G.J. (2006). Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: a review. Water Research 40(1): 3–22.
- Signify/Philips (2024). TUV T5 germicidal lamp specifications — 9,000 h useful life.
Questions we get about the Spectrum UV
W or WU?
WU includes the 2" (or 3") union set; W is the bare unit for your own fittings. Same reactor and ballast.
Clarifier or sterilizer?
At the flow ratings above it clears green water. Halve the flow (longer dwell) and the same unit approaches sterilizer dose for pathogen control.
Which lamp?
40 W = Philips TUV 36T5 HE; 75 W = TUV 36T5 HO. The 150 W takes two HO lamps, the 300 W four.
Matala at Mystic Koi
Matala filter media and pond equipment have been a koi-keeping staple for decades, and Mystic Koi has sold and run Matala gear in our own systems since we opened in Upland, California in 1996. Everything on this page ships from Matala USA (Sea Life Designs) or our ¾-acre facility. Not sure what fits your pond? Call or visit and we’ll size it with you.