UNS · Stone
Ancient Stone
Iwagumi keepers who like the Manten look and want a slightly darker, more angular stone.
4 models
UNS · Stone
UNS Black Mountain Seiryu Stone
A near-black Seiryu variety with blue undertones and the same grooves and jagged forms as the classic grey stone. The dark colour makes bright green and red plants stand out.
Updated
Best for
Iwagumi and nature layouts where you want Seiryu shapes in a darker, moodier colour.
Worth knowing
Raises hardness like normal Seiryu, so skip it for Caridina or soft-water fish.
What stands out
- 10, 20 and 30 lb lots
- Charcoal to almost black with a blue tinge
- Classic Seiryu grooves and shapes
- Works alone or with driftwood
Models and specs
| Model | Weight |
|---|---|
| 10 lbBMS0010 | 4.5 kg |
| 20 lbBMS0020 | 9.1 kg |
| 30 lbBMS0030 | 13.6 kg |
- Brand
- UNS
- Effect on water
- Raises KH, GH and pH (calcareous, like all Seiryu-type stone)
- Colour
- Charcoal to near black, blue undertone
- Texture
- Grooved, jagged
- 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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Shrimp and nano tanks that need hiding spots, or scapers wanting planted pockets at different heights.
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Frequently asked questions
Quick answers about the UNS Black Mountain Seiryu Stone, drawn from its specs.
Does Black Mountain Seiryu Stone affect water chemistry?
Raises KH, GH and pH (calcareous, like all Seiryu-type stone).
How do I prepare Black Mountain Seiryu Stone before use?
Rinse and scrub well before use
Who is the UNS Black Mountain Seiryu Stone best for?
Iwagumi and nature layouts where you want Seiryu shapes in a darker, moodier colour.
Is there anything to watch out for with the UNS Black Mountain Seiryu Stone?
Raises hardness like normal Seiryu, so skip it for Caridina or soft-water fish.
What are the alternatives to the UNS Black Mountain 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.