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Named evidence gapWhat GH, KH, pH and conductivity combinations are true biological optima?
A precise unanswered question is part of the source of truth. It prevents an absent study, indirect result or popular rule from becoming false certainty.
This is a current search boundary, not proof that no study exists. The dated searches below show what was checked, which candidates were included or excluded and what evidence would change the answer.
Current boundary
Field occurrences and study culture water describe places or reproducible conditions, not species-wide GH, KH, pH or conductivity optima.
What would answer it
Factorial, replicated exposures across lines and life stages with measured ions and long-term biological endpoints.
Answerability brief
Specialist-led research is required
The question requires specialist identification, analytical verification, welfare oversight or treatment authority beyond an ordinary keeper observation.
Decision at stake: Whether GH, KH, pH or conductivity combinations can be called biological optima rather than occurrence or house operating ranges.
Primary endpoint: Multigeneration reproductive output and survival, with growth, molting and offspring condition reported separately.
Minimum design: Factorial, independently replicated ion-defined treatments across more than one documented line and life stage, with acclimation separated from chronic exposure.
Required reporting: Measured calcium, magnesium and other relevant ions, alkalinity, pH method and time series, conductivity, temperature, nitrogen, source line, allocation, independent tanks, complete reproductive denominators and uncertainty.
Community can contribute: Method-labelled source-water and remineralization records can identify common combinations and prevent implausible experimental treatments.
Community observations cannot establish: A GH, KH, pH or TDS number from unrelated tanks cannot isolate ions, prove causation or reveal an optimum.
Closure rule: The term optimum remains unavailable until factorial long-term biological response surfaces are replicated across documented lines.
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Current research allocation
Qualified collaboration required
The current publisher cannot answer this alone. Work waits for suitable facilities, expertise, oversight and independently replicated units.
Why this allocation: An optimum requires ion-defined factorial response surfaces across documented lines, beyond the chemistry control available in ordinary community tanks.
Next permitted unit: Develop an analytical and factorial design question with a water-chemistry and experimental-design specialist.
Activation trigger: A suitable laboratory can verify ion composition and support replicated multigeneration treatments across documented source lines.
Stop decision: Stop adding occurrence ranges, seller recipes or GH, KH and TDS surveys that cannot identify ions or estimate an optimum.
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Reviewed: August 12, 2026.
Topics: Nitrogen waste, Growth and lifespan, Breeding
Practical guides governed by this gap
Reproducible search trail
Do direct experiments establish combined GH, KH, pH and conductivity optima for Neocaridina?
Taxon names: Neocaridina davidi, Neocaridina heteropoda, Neocaridina denticulata sinensis.
Concepts: hardness, GH, KH, pH, conductivity, growth, reproduction.
Search surfaces: publisher and DOI records, PubMed, scholarly web indexes, full-text repositories.
Outcome: The occurrence boundary is broader, but no replicated factorial water-parameter optimum study was located. Field ranges and culture values remain contexts rather than targets.
Exact queries and candidate decisions
Exact queries
Neocaridina davidi hardness pH conductivity experiment growth reproduction"Neocaridina heteropoda" water hardness GH KH experiment"Neocaridina denticulata sinensis" pH salinity water quality growth
Candidate sources
- Life-history traits and ecological characteristics of the ornamental shrimp Neocaridina denticulata, recently introduced into the freshwater systems of Israel: included. Adds field occurrence and laboratory culture conditions, but neither was an assigned water-parameter optimum experiment.
- Effect of temperature on biochemical composition, growth and reproduction of the ornamental red cherry shrimp: included. Varies temperature while water chemistry remains context, so it cannot identify a GH, KH, pH or conductivity optimum.
Next scheduled search: February 12, 2027. Also governs: water-parameter-optima
Help close or refine this gap
Submit a stable source or correction. A title, abstract or community consensus does not close the gap until its methods and claim boundary are reviewed.