AquaFX Blue Fin — Light-Commercial 500GPD 4-Stage RO/DI System
500 Gallons of 0 TDS Water a Day. No Booster Pump Required. Hand-Built in the USA.
The straightforward, high-volume workhorse between a residential RO/DI unit and full commercial output — built for coral farmers, aquarium stores that don't sell water, and hobbyists running large systems who need a lot of water without a lot of complexity.
Why the Blue Fin
Most systems in this output range either force you into a booster pump to hit usable production, or bury you in stages and consumables you don't need. The Blue Fin keeps it simple: 500GPD at standard household pressure (65 PSI) — more than double the output of a standard 10x2 RO/DI system — in a lean 4-stage design that's easy to maintain and easy to budget for.
Who it's for:
- Small-to-medium coral farms that need serious volume without a full commercial footprint
- Aquarium stores that don't retail water to customers
- Hobbyists running large or multiple display tanks who've outgrown a residential unit
- Anyone who wants Blue Fin PRO-level output with a simpler, lower-cost filtration stack
Need dual carbon stages for heavier chloramine loads, or a larger DI capacity? See the Blue Fin PRO (7-stage). Running a retail water station or need even higher throughput? Step up to the Blue Marlin or Blue Marlin PRO.
Key Advantages
|
Blue Fin (4-Stage) |
| Output |
500 GPD @ 65 PSI, 77°F, 250 ppm TDS |
| Booster pump required? |
No — recommended only under 45 PSI |
| Filter size |
Larger 10"x4" pre-filter, carbon block & DI resin (vs. standard 10"x2") |
| Filter life |
Longer contact time = fewer cartridge changes |
| Final water quality |
0 TDS, zero phosphate, laboratory-grade |
| Build |
Hand-built in the USA, heavy-duty steel mounting bracket |
| Footprint |
25"W x 8"D x 18.5"H |
| Stages |
4 — sediment, carbon block, RO membrane, mixed-bed DI |
The larger 10"x4" cartridges aren't just about capacity — longer water contact time per stage means cleaner output and cartridges that last longer between changes, so you're spending less time (and money) on maintenance than with a standard 10x2 setup.
How It Works — 4 Stages of Filtration
| Stage |
Function |
| 1 |
AquaFX Premium 1-Micron Sediment Filter — 10"x4" |
| 2 |
AquaFX Chlorine Guzzler Carbon Block Pre-Filter — 10"x4" |
| 3 |
AquaFX TFC 500GPD Light-Commercial RO Membrane (Made in USA) |
| 4 |
AquaFX Mixed-Bed Color-Indicating Zero-TDS DI Resin (USA Resin) — 10"x4" |
Color-indicating DI resin means you'll see when the cartridge needs changing — no guesswork, no TDS creep catching you off guard.
Features
- Hand-built in the USA by AquaFX
- 0 TDS, zero-phosphate, ultra-pure laboratory-grade output
- Large 10"x4" pre-filter, carbon block, and DI cartridge for longer service life
- Heavy-duty steel mounting bracket
- Back-lit triple TDS meter — monitor tap, RO, and final DI readings at a glance
- Quick-disconnect check valve
- Automatic shut-off kit
- Adjustable flow restrictor
- Pressure gauge with quick-connect fittings
Specifications
-
Filtration: 4-stage
-
Dimensions: 25"W x 8"D x 18.5"H
-
Inlet & product lines: 3/8" | Waste line: 1/4"
-
Fittings: Quick-connect throughout
-
Rated output: 500 GPD @ 65 PSI, 77°F, 250 ppm TDS input over 24 hours (lower pressure, colder water, or higher source TDS will reduce output — a high-flow booster pump is recommended below 45 PSI)
What's Included
- AquaFX Blue Fin RO/DI system with all 4 filter stages installed
- Back-lit triple TDS meter
- Hose bib adapter
- 10" canister filter wrench for fast, easy filter changes
- 6 ft each of supply, drain, and product tubing
- AquaFX instruction manual
Need additional feed/drain fittings for your install? See compatible installation parts here.
FAQ
Do I need a booster pump? Not at standard household pressure (65 PSI). Below 45 PSI, a high-flow booster pump (3/8" inlet/outlet) is recommended to maintain rated output.
How is this different from the Blue Fin PRO? The Blue Fin PRO adds a second carbon stage and splits DI into three dedicated cation/anion/mixed-bed cartridges for heavier chloramine municipal water and maximum DI capacity. The standard Blue Fin covers the same 500GPD output with a leaner 4-stage design — a great fit if your source water isn't especially chloraminated and you want a lower-cost, lower-maintenance system.
How is this different from a standard 10x2 RO/DI system? The Blue Fin's 10"x4" cartridges more than double the media volume of a standard 10x2 system, giving you both higher output and longer filter life between changes.
Will this work for my retail fish store? If you sell water to customers, we'd recommend stepping up to the Blue Marlin or Blue Marlin PRO for the added throughput. The Blue Fin is built for coral farms, non-water-retail stores, and large home systems.
Questions on sizing this system for your setup? Reach out to our team — World Wide Corals stocks AquaFX systems and genuine replacement cartridges.
