GC Tek · Grand Champion Technologies
The filter behind serious koi ponds.
AlphaONE, AquaBead and AlphaNANO pressure filters, pre-plumbed WattMizer systems, 316-stainless UV and the parts to keep them running for decades. Built in Chandler, Oklahoma. Sold, set up and supported by Mystic Koi.
Built to order. Freight quoted, never guessed.
Most GC Tek filters and systems are assembled after you order. Here's exactly how it goes.
Shop by category
Everything GC Tek makes, one place
Filters
AlphaONE · AquaBead · AlphaNANO · X2 · Megladon · NishikigoiRDF drums · Wakimizu showers
Complete systems
KoiKeeper · PLUS · PLUS PRO · PondKeeper — filter, pump and UV on a pad
Polishing & carbon
PoliGlassBead glass-bead polisher · UniClear carbon filter for tannin color
UV clarifiers
NishikigoiUV 316 SS amalgam (H & V) · ZapPRO · Zapp Pure · lamps & parts
Prefilters
AquaSieve2 · AquaSieve 3.3 SS · MultiCyclone 50
Pumps, air & heaters
WunderMax variable speed · NishikigoiAIR · ThermaKoi ZappHeat heaters
TheLiberator
Automatic backwash — pump off, agitate, backwash, rinse, reset. From your phone.
Parts, media & plumbing
Multiports, spider gaskets, lids, agitators, spring checks, media by the cu ft
Sizing helper
Which GC Tek filter does my pond need?
GC Tek rates 1 cu ft of media for about 50 lb of koi fed 1% of body weight a day. Enter your gallons, tell us how you keep fish, and we'll point you at the right size and its pre-plumbed system.
We'll show the filter size, the matching WattMizer system, and what to expect on lead time.
Start here
The GC Tek line-up
AlphaONE / AquaBead / AlphaNANO Pressure Filter
One tank, three media, five sizes, standard or LH valve. The filter GC Tek sells 48 times out of 50.
WattMizer PLUS System
Filter + Artesian2 pump + NishikigoiUV-HD160 pre-plumbed on a pad, with or without AquaSieve2.
WattMizer PLUS PRO System
Dual AquaSieve2 prefilters and a 3-port balance valve — five minutes a week.
X2 Pressure Filter (formerly Medusa)
Two pumps on one filter, nothing narrower than 2" in either path. To 30,000 gal.
PoliGlassBead Polishing Filter
True glass beads to 3 microns. Bottom drain visible at 6 feet.
ZapPRO 116 W HO Dual-Lamp UV
Two 58 W HO lamps, 7,800 gph, 13,000-hour lamps, fault protection.
AquaSieve Solids-Separator Prefilter
The solids separator that turns a daily pump-basket chore into a monthly one.
ThermaKoi ZappHeat Inline Pond Heater
316 SS inline heaters with flow switch and digital thermostat. 1.5 to 18 kW.
Filter Media — BioGems / AlphaBioONE / AlphaNANO
BioGems, AlphaBioONE and AlphaNANO by the quarter, half and full cubic foot.
The Nishikigoi line · 錦鯉
GC Tek finally built the drum, the shower and the stainless UV.
Japanese-style koi filtration, engineered in Oklahoma at GC Tek prices: a rotating drum filter for solids, a Wakimizu bakki shower for biology, marine-grade 316 stainless amalgam UV, and premium air. Pair a drum with an AlphaONE or a shower and you have the system the breeders run.
NishikigoiRDF drum filter
75-micron 316 SS screen, automatic backwash, 2,500 to 100,000 gal. Polypropylene or stainless.
Wakimizu bakki shower
Drip-tray top tier, elevated media support, hidden back plumbing. 15 to 80 inch, PP or 316 SS.
NishikigoiUV — 316 SS amalgam
1 to 6 amalgam lamps, one ballast per lamp, hour meter, lifetime vessel warranty. Horizontal or vertical.
NishikigoiAIR pumps
Aluminum-cased, quiet, 30 to 160 L/min. Feeds air rings, showers and the ALISS valve.
Why GC Tek
More than a bead filter
Every GC Tek pressure filter ships with the features other brands sell as upgrades — or don't offer at all.
Omnifuser internals
No slotted laterals and no elbows inside the tank. Water enters at the lowest point and exits at the highest, so the whole media bed works and solids gather at the bottom center where backwash purges them. The lowest-head filters on the market.
2 HP media agitator
A 100+ CFM regenerative blower tumbles the media on backwash. Beads never pack or channel, bacteria keep their surface area, and the weekly clean is three minutes with clean hands.
ALISS life support
The AlphaONE Life Support System valve lets your air pump keep the media oxygenated during a pump failure or medical bypass. Bacteria survive; the pond doesn't crash.
Lifetime tank warranty
Molded fiberglass with a second spun-fiberglass shell, pressure rated to 58 psi. Limited lifetime warranty on the tank and a 1-year satisfaction guarantee. Clear 10" lid, true-reading gauge, EZ Drain.
AlphaONE vs AquaBead vs AlphaNANO
Same tank. Pick the media that fits how you keep koi.
AlphaONE
- AlphaBioONE media — open-cell, dimpled, air-injected.
- Distributes debris through the whole bed, not the top few inches.
- Doesn't slow down between backwashes like classic beads.
- What GC Tek and most koi keepers pick.
AquaBead
- BioGems media — small floating bead, huge surface area.
- Tighter capture for keepers chasing the last bit of polish from the bead bed.
- Slightly higher operating pressure.
- Convertible to AlphaONE later with a retro kit.
AlphaNANO
- AlphaNANO media — BioGems-sized, molded like AlphaBioONE.
- 600+ sq ft of surface per cubic foot.
- Field-tested by contractors for over a year; "a polishing filter that flows like an AlphaONE".
- Same price as the other two.
The Mystic Koi advantage
Buy it from people who run these filters.
- ✓Warranty and repairs handled hereWe're an authorized dealer. Warranty claims and parts go through us and the factory — you don't ship a tank across the country.
- ✓Honest MAP pricing, distributor-directGC Tek sets minimum advertised prices and we sell at them, to the penny. No fake "sale" markdowns, no bait pricing.
- ✓Freight confirmed before it shipsWe quote LTL to your door and you approve it. Or pick up free in Upland, CA.
- ✓Sizing and setup helpCall the shop with your gallons, fish load and pump and we'll spec the filter, UV and prefilter that actually fit — and plumb-in diagrams if you want them.
authorized dealer
Good to know
Questions we get every week
How long does a GC Tek filter take to arrive?
Filters and pre-plumbed systems are assembled to order at the factory in Chandler, Oklahoma — plan on about 3 weeks to ship, then freight transit. GC Tek fills orders strictly in the order received. Parts, media and UV lamps we stock ship from Upland within a day or two.
Why isn't freight charged at checkout?
Freight on a 100–300 lb crate depends on your ZIP, residential vs. commercial delivery and whether you need a liftgate. Rather than overcharge some customers with a flat guess, we quote the real number and confirm it with you before anything ships. Local pickup is always free.
AlphaONE or AquaBead?
Same tank, same valve, same price. AlphaONE (AlphaBioONE media) flows more freely and spreads debris through the whole bed — it's what GC Tek sells 48 times out of 50. AquaBead's smaller BioGems beads capture a bit finer at slightly higher pressure. AlphaNANO gives you BioGems-sized media with AlphaONE's open-cell shape. Unsure? AlphaONE.
Should I get the LH (lower head) valve?
If electricity cost matters to you, yes. LH bypasses the multiport in normal filtration, so you can run a smaller, lower-amp pump for the same turnover. Same ratings, same media.
What size do I need for koi?
GC Tek's rule is 1 cu ft of media per ~50 lb of koi. Koi ponds run heavier than water gardens — when you're between sizes, go up. Use the sizing helper above or call us.
What UV comes with the systems now?
As of June 2026 every KoiKeeper and PondKeeper system ships with the 316-stainless NishikigoiUV-H80 amalgam UV, and PLUS / PLUS PRO systems ship with the NishikigoiUV-HD160. Individual ballasts per lamp, lamp indicators and an hour meter are standard.