Our take
The legacy JBJ RL-20 is a specialist shallow frag aquarium: historical sources describe a 20-gallon rimless tank with a broad 20-by-24-inch footprint, roughly 9-inch height and rear three-stage filtration. A MarineDepot support post lists a pump and frag rack. Those details make it meaningfully different from a standard glass tank, but the sources are from 2013 and do not verify the frozen Amazon ASIN as a current offer or prove what a present seller includes.
A buyer comparing a legacy shallow frag-tank layout who can verify the model, dimensions and included components of the actual unit..
It is not a verified current kit, a tall display format, a separate sump system, or the later JBJ Nano RL NRL-20 model.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- The model-specific reports give a 20-gallon capacity and a shallow, wide footprint for frag layouts.
- The MarineDepot post describes three rear filtration chambers and names several included legacy components.
- The RL-20 code distinguishes it from the later NRL-20 Nano RL and the NRL-15 candidate.
What to weigh up
- The source material is historical and does not verify current production, stock, or the present seller package.
- A source recommends a Pacifica LED, but no light is listed as included.
- The support post describes rear AIO chambers, not a separate sump.
The key details
| Model covered | RL-20 |
|---|---|
| Listed Capacity | 20 gal nominal |
| Tank Construction | Rimless glass; 6-mm curved corners listed |
| Documented Package Feature | Three rear chambers; legacy support post lists pump and frag rack |
Performance figures are manufacturer claims. Source checked October 8, 2026. Regional models and included accessories can differ.
What the features mean for you
Keep the legacy RL-20 separate from JBJ's Nano RL models
The candidate title and saved model clue name RL-20. Reef Builders' 2013 report describes that legacy model as a 20-gallon rimless frag aquarium. A MarineDepot support post uses the full name JBJ Rimless Aquarium Series, Model RL-20 and lists its equipment. JBJ's newer Nano RL line uses model codes such as NRL-20 and NRL-15; those names are close but are not the same product identifier. This review does not transfer the newer line's low-iron-glass or current warranty specifications to the older frag tank. Compare the printed model code and historical configuration when searching.
A shallow footprint changes how the display is arranged
Reef Builders gives the tank a 20-by-24-inch footprint and an approximate 9-inch height. The report presents the shorter, wider form as useful for housing coral frags, and the MarineDepot post describes a black egg-crate rack with riser feet. That combination suggests a layout built around accessible horizontal working space rather than the height of a conventional aquarium. It does not establish which livestock can be kept, how many pieces will fit in a real setup, or whether a specific light reaches a target intensity. Confirm exact dimensions and plan the support surface before buying a used or current unit.
The rear filtration is integrated into the tank
The MarineDepot post describes an all-in-one three-chamber filter section at the back and a 16-watt pump rated at 266 gallons per hour in the original product details. It also lists a large sponge as mechanical media. Those are source-stated specifications, not performance measurements from this review, and the age of the post makes current package verification essential. Rear chambers can help keep listed filtration components within the tank footprint, but the same source does not call this a separate sump. It therefore appears in flexible and glass-only paths, not in the finder’s sump-required answer.
Separate the listed lids and rack from the light recommendation
The MarineDepot post names a black chamber lid, a tempered-glass cover with clips, an egg-crate rack and PVC riser feet. It says JBJ recommends a Pacifica LED and that the cover is cut for its mounting bracket. A recommendation is not an included light, so this profile leaves lighting unknown. A shopper should request photographs of the actual cover, clips, rack, pump and model label before assuming that a decades-old package remains complete. Missing or replaced pieces can change how the tank is used and what additional parts need to be sourced.
How the RL-20 differs from standard glass tanks
AAG10015 is a standard 15-gallon glass aquarium with no equipment bundle established by its catalog crosswalk. Aqua Japan AJ-50 is also listed at 15 gallons but has rear chambers and a return-pump gap. RL-20 is larger by its listed nominal capacity and has a purpose-described shallow frag layout with a historical pump and rack list. These documented contrasts explain why the model can be relevant to reef-frag shoppers while still appearing in the broad 10-gallon-plus glass comparison. They do not rank the models or prove that any one is appropriate for a particular coral.
What else to compare
For a 15-gallon standard glass tank compare AAG10015; for a 15-gallon glass all-in-one layout with a return-pump gap compare Aqua Japan AJ-50. Both have different capacities and package details from the shallow RL-20.
Before you buy
Is RL-20 the same as JBJ NRL-20?
No model crosswalk is supported. RL-20 is the legacy frag aquarium in the historical sources; NRL-20 is a later Nano RL model code.
Does RL-20 include a light?
The MarineDepot post recommends a Pacifica LED and describes a compatible cover bracket, but does not list the light as included.
Does its rear filter count as a sump?
The source calls it an all-in-one three-chamber filtration system at the back. It does not identify a separate sump, so the sump-required path excludes it.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources & review basis
We use the following manufacturer documentation for the product features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- MarineDepot JBJ RL-20 product-support post and Reef Builders report ↗ — checked October 8, 2026.
- Reef Builders report, legacy RL-20 20-gallon rimless tank, 20 × 24-inch footprint and approximate 9-inch height ↗ — checked October 8, 2026.
- MarineDepot support post identifying model RL-20, three rear chambers, glass details, lids, egg-crate rack and pump specifications ↗ — checked October 8, 2026.
The decision
RL-20 is a distinct shallow frag-tank candidate supported by historical model-specific sources. Verify its code, present condition, dimensions and every included part; the tagged model search does not claim that the frozen Amazon ASIN is a current exact offer.
Is it the right fit?
Check the exact model and today’s offers on Amazon.