Seachem Silicate Kit 75 tests
Pack size
75+ tests
Water type
Freshwater + Marine
Seachem Silicate Kit 75 tests
Tracks the silicate that feeds diatom algae in reef and freshwater tanks. Seachem's Silicate MultiTest kit uses a colour-comparison method and multi-cavity test plate, giving reef and freshwater keepers a way to check silicate before brown diatom films take hold.
Key features
- 75+ tests per kit – works out to roughly 53c per test
- 0–25 mg/L measuring range – covers everything from ultra-low reef targets to natural freshwater levels
- Fine resolution – detects colour changes in 0.1–1 mg/L and 0.01–0.1 mg/L increments, with a detection limit below 0.5 mg/L
- Freshwater and marine suitable – one kit covers both reef and freshwater/planted setups
- Multi-cavity test plate – run up to six tests at once
- Included reference sample – lets you check reagent accuracy is still reliable, not just learn the colour chart
- Why it matters – silicate is non-toxic to fish and invertebrates but feeds diatomaceous (brown) algae, so reef keepers keep it low to limit outbreaks
Specifications
| Attribute | Detail |
|---|---|
| Tests per kit | Over 75 |
| Measuring range | 0–25 mg/L silicate |
| Resolution | 0.1–1 mg/L and 0.01–0.1 mg/L increments on the colour chart |
| Detection limit | Less than 0.5 mg/L |
| Reagent type | Liquid reagents 1a, 1b, 2 and 3 |
| Water type | Freshwater and marine |
| Kit format | Multi-cavity test plate, up to 6 simultaneous tests |
| Includes | Reagents, reference sample, colour chart, cuvette, sample pipette, stir rod |
Target silicate levels
| Setup type | Guidance |
|---|---|
| Reef / marine aquarium | 1 mg/L or less, to minimise diatomaceous algae |
| Freshwater aquarium | Not considered critical; natural levels typically sit around 4–20 mg/L |
Suitable for
- Reef and marine aquarists monitoring silicate to control diatom outbreaks
- Freshwater and planted tank keepers who want a baseline silicate reading
- Anyone checking whether RO/DI resin or a silicate-removing media is still working
Not suitable for
- Testing other parameters such as phosphate or nitrate – separate Seachem MultiTest kits are needed for those
- Aquarists wanting lab-grade ICP-level precision rather than a colour-comparison test
Directions for use
Add an aquarium water sample to the multi-cavity test plate, then add reagents 1a, 1b, 2 and 3 in the order set out in the instructions packed with the kit. Let the reaction develop, then compare the colour against the printed colour chart or the reference sample to read off the silicate level in mg/L.
Storage
Keep reagents cool and out of direct light, as heat and light exposure can affect analytical reagents over time. Use the included reference sample periodically to confirm your reagents are still giving accurate results.
Warranty
This kit is covered by the consumer guarantees under Australian Consumer Law, in addition to any support Seachem provides for manufacturing defects. Contact us if you have any concerns about reagent performance or kit contents.
Common questions
What does silicate cause in my tank
Silicate itself is non-toxic to fish and invertebrates, but it feeds diatoms, the brown, dust-like algae that commonly appears on glass, sand and rock in newer marine setups.
Does this kit work for both freshwater and saltwater
Yes. Seachem's Silicate MultiTest is designed for both freshwater and marine aquariums.
Why is silicate less of a concern in freshwater tanks
Freshwater silicate levels are naturally higher, typically around 4–20 mg/L, and Seachem does not treat freshwater silicate as a critical parameter the way it is in reef systems.
How often should I test silicate
Reef keepers commonly test after water changes, when adding new sand, rock or media, or whenever a brown dusty film starts appearing on glass or substrate, since that film is usually diatom algae fed by silicate.
