Liquid Carbon Toxicity
'Liquid carbon' (sold as a CO2 alternative or algaecide) contains glutaraldehyde or similar polymers. While tolerated by many plants at recommended doses, it acts as a mild biocide that destroys the cellular structure of algae. Some very primitive aquatic plants or those with thin cuticles cannot tolerate the chemical aggression of glutaraldehyde, even at minimum doses. Overdosing, often used to fight algae, leads to irreversible tissue liquefaction.
Plant profile
Resolution Difficulty
Observe and distinguish
Identification and context
Signs and distribution
Disintegration and almost immediate melting of the leaves, which become translucent and gelatinous before pulverizing. This selectively affects specific species, while tough-leaved plants (Anubias, Bucephalandra) remain intact. A dramatic rapid 'melt' is observed, usually within 24-48 hours of product addition.
Affected tissue and growth
Disintegration and almost immediate melting of the leaves, which become translucent and gelatinous before pulverizing. This selectively affects specific species, while tough-leaved plants (Anubias, Bucephalandra) remain intact. A dramatic rapid 'melt' is observed, usually within 24-48 hours of product addition.
Physiology or exposure
'Liquid carbon' (sold as a CO2 alternative or algaecide) contains glutaraldehyde or similar polymers. While tolerated by many plants at recommended doses, it acts as a mild biocide that destroys the cellular structure of algae. Some very primitive aquatic plants or those with thin cuticles cannot tolerate the chemical aggression of glutaraldehyde, even at minimum doses. Overdosing, often used to fight algae, leads to irreversible tissue liquefaction.
Verify before intervening
Confirmation and decisions
Differential diagnosis
Compare sign distribution, leaf age, mechanical damage, emersed-to-submersed adaptation, algae, pests and multiple concurrent deficiencies.
How to verify
Confirm with a photographic timeline, repeated measurements and one controlled change at a time; an isolated leaf sign does not automatically identify the cause.
Proportionate actions
Management and monitoring
What to do now
Stabilize light, CO₂, temperature and water quality; remove only decaying tissue. Avoid concentrated corrections or several simultaneous changes.
Controlled correction
Immediately suspend liquid carbon dosing. Perform a substantial water change (50%) to dilute the active ingredient. Surgically remove all liquefied leaves and stems with scissors to prevent an ammonia spike from decomposition. Adding fresh activated carbon to the filter will remove chemical residues within hours.
New-growth response
If you keep Vallisneria, Egeria, or sensitive mosses, completely avoid using Excel or EasyCarbo. If using it to fight algae, apply it locally via syringe with the filter off (spot-treatment) directly onto the algae, rather than dosing the entire water column. Never exceed bottle dosages.
Prevention
If you keep Vallisneria, Egeria, or sensitive mosses, completely avoid using Excel or EasyCarbo. If using it to fight algae, apply it locally via syringe with the filter off (spot-treatment) directly onto the algae, rather than dosing the entire water column. Never exceed bottle dosages.
When to escalate
Escalate if deterioration is rapid, involves the rhizome or stem, produces foul odor, or coincides with animal distress or detectable ammonia/nitrite.