UNS · Stone
Ancient Stone
Iwagumi keepers who like the Manten look and want a slightly darker, more angular stone.
4 models
UNS · Stone
UNS Seiryu Stone
The classic Iwagumi stone: blue-grey with white veins, sharp ridges and deep grooves. It comes in every size from nano pebbles to big main stones and works just as well at the foot of driftwood.
Updated
Best for
Iwagumi and nature layouts in tanks where a little extra hardness is fine, such as most community fish and Neocaridina setups.
Worth knowing
Raises KH and pH over time, so it is a poor choice for Caridina shrimp or soft-water specialists.
What stands out
- 5, 10, 20 and 30 lb lots plus a 3 lb bag of small accent pieces
- Blue-grey with white calcite veins
- Jagged, grooved shapes with lots of character
- Suits tanks from 4 litre cubes to large standards
Models and specs
| Model | Weight | Piece size |
|---|---|---|
| 5 lbBSS0005 | 2.3 kg | – |
| 10 lbBSS0010 | 4.5 kg | – |
| 20 lbBSS0020 | 9.1 kg | – |
| 30 lbBSS0030 | 13.6 kg | – |
| Accent pieces (3 lb)UNSAS031 | 1.4 kg | 2.5-7.5 cm |
- Brand
- UNS
- Effect on water
- Raises KH, GH and pH (calcareous, like all Seiryu-type stone)
- Colour
- Blue-grey with white veins
- Texture
- Jagged, grooved
- Origin
- China
- Prep
- Rinse and scrub well before use
Figures from Glass Aqua's product listing. Makers revise products, so check the current figures before buying. Photos supplied by the brand or its distributor.
What seiryu stone does to your water
It contains calcium carbonate, so it dissolves slowly and pushes pH and general hardness up over time. The effect is stronger in soft, low-buffered water. If you are aiming for a soft-water shrimp or blackwater tank, seiryu will fight you; for a harder community it is fine. Test with a drop of acid, it fizzes.
Full Seiryu Stone guideCompare with
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UNS · Stone
Ashen Stone
Minimal or river-style scapes that want bright, soft stone against lush green planting.
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Black Lava Rock
Budget-friendly builds, nano tanks and moss-covered scapes that need plenty of stone volume.
1 model
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Black Lava Rock Cave
Shrimp and nano tanks that need hiding spots, or scapers wanting planted pockets at different heights.
4 models
Frequently asked questions
Quick answers about the UNS Seiryu Stone, drawn from its specs.
Does Seiryu Stone affect water chemistry?
Raises KH, GH and pH (calcareous, like all Seiryu-type stone).
How do I prepare Seiryu Stone before use?
Rinse and scrub well before use
Who is the UNS Seiryu Stone best for?
Iwagumi and nature layouts in tanks where a little extra hardness is fine, such as most community fish and Neocaridina setups.
Is there anything to watch out for with the UNS Seiryu Stone?
Raises KH and pH over time, so it is a poor choice for Caridina shrimp or soft-water specialists.
What are the alternatives to the UNS Seiryu Stone?
Other hardscape worth comparing: UNS Ancient Stone, UNS Ashen Stone, UNS Black Lava Rock. Add any of them to the compare table to see the specs side by side.