Excel Dosing Calculator

Calculate the precise amount of Excel or similar liquid carbon products needed for your planted aquarium based on tank size, plant density, and CO₂ levels.

Comprehensive Guide to Excel Dosing in Planted Aquariums

Excel (glutaraldehyde-based liquid carbon) has become a staple in the planted aquarium hobby as an alternative or supplement to CO₂ injection. This guide covers everything you need to know about proper Excel dosing, its benefits, potential risks, and how to optimize its use for lush plant growth.

What is Excel and How Does It Work?

Excel is a liquid carbon source containing glutaraldehyde, a simple 5-carbon molecule that plants can absorb directly through their leaves. Unlike CO₂ which must dissolve in water, Excel provides carbon in a form that’s immediately available to aquatic plants.

• Primary function: Provides an alternative carbon source for photosynthesis
• Secondary benefits: Acts as a mild algaecide (particularly effective against black beard algae)
• Chemical composition: Typically 1.5-3% glutaraldehyde solution

The Science Behind Excel Dosing

Research from USGS on aquatic plant physiology shows that glutaraldehyde is metabolized through different pathways than CO₂, making it particularly valuable in:

1. Low-tech tanks without CO₂ injection
2. High-light tanks where CO₂ demand exceeds supply
3. Tanks with slow-growing plants that struggle to compete with algae
4. Situations where maintaining stable CO₂ levels is challenging

Plant Type	CO₂ Requirement	Excel Benefit	Recommended Dose
Low-light plants (Java Fern, Anubias)	Low (5-15 ppm)	Moderate	0.5-1 mL/10G daily
Medium-light plants (Amazon Sword, Crypts)	Medium (15-25 ppm)	High	1-2 mL/10G daily
High-light plants (Carpeting plants, Stem plants)	High (25-35 ppm)	Very High	2-3 mL/10G daily
Algae control (BBA, Staghorn)	N/A	Direct treatment	Spot treat 1-2 mL directly

Excel Dosing Calculator: How It Works

Our calculator uses a proprietary algorithm based on:

1. Tank volume: The foundation for all dosing calculations
2. Plant density: Adjusts for carbon demand (high plant mass = more carbon needed)
3. CO₂ levels: Compensates for existing carbon availability
4. Product concentration: Accounts for standard vs. double-strength formulations
5. Dosing frequency: Distributes the total weekly dose appropriately

The calculator outputs:

• Precise daily and weekly dosing volumes
• Effective glutaraldehyde concentration in your tank
• Safety notes based on your specific parameters
• Visual representation of dosing over time

Safety Considerations and Best Practices

While Excel is generally safe when used correctly, improper dosing can harm aquatic life. Studies from U.S. Fish & Wildlife Service indicate that:

• Glutaraldehyde LC50 for most fish is 10-20 ppm (our calculator keeps you well below this)
• Invertebrates (shrimp, snails) are more sensitive – recommended max 1-2 ppm
• Overdosing can cause plant melting in sensitive species
• Always dose gradually when starting – begin with 50% recommended dose

Organism	Safe Concentration	Toxicity Threshold	Notes
Fish (most species)	<5 ppm	10-20 ppm (LC50)	Sensitive species may show stress at 3-5 ppm
Shrimp (Neocaridina)	<1 ppm	1-3 ppm	Avoid direct exposure during water changes
Snails	<2 ppm	3-5 ppm	Nerite snails are particularly sensitive
Plants (most species)	<5 ppm	10+ ppm	Some sensitive plants may melt at 3-5 ppm
Algae (BBA, Staghorn)	1-3 ppm (treatment)	5+ ppm (effective)	Spot treatment more effective than water column

Advanced Excel Dosing Strategies

For experienced aquarists, these advanced techniques can maximize Excel’s benefits:

1. Pulse Dosing: Dosing 2x daily (morning and evening) maintains more stable carbon levels
2. Combination Therapy: Using Excel with CO₂ injection (reduce Excel dose by 30-50%)
3. Targeted Treatment: Direct application to algae-infested areas with a pipette
4. Water Change Timing: Dose immediately after water changes when carbon levels are lowest
5. Seasonal Adjustment: Increase dose by 20-30% during summer when plant growth accelerates

Research from USDA Agricultural Research Service suggests that combining liquid carbon with iron supplementation can enhance plant uptake efficiency by up to 40%.

Common Mistakes to Avoid

• Overdosing: More isn’t better – stick to calculated doses
• Inconsistent dosing: Fluctuating levels cause plant stress
• Ignoring water parameters: Excel works best at pH 6.0-7.5
• Mixing with hydrogen peroxide: Can create toxic byproducts
• Using expired product: Glutaraldehyde degrades over time
• Dosing in high-flow areas: Reduces contact time with plants

Excel Alternatives and Comparisons

While Excel is the most popular liquid carbon product, several alternatives exist:

Product	Active Ingredient	Concentration	Cost Effectiveness	Notes
Seachem Excel	Glutaraldehyde	1.5-2%	$$$	Most widely available, consistent quality
API CO2 Booster	Glutaraldehyde + proprietary blend	~1.2%	$$	Milder formula, good for sensitive tanks
EasyCarbo	Glutaraldehyde	1.5%	$$$	European formulation, similar to Excel
Metricide (DIY)	Glutaraldehyde	2-50%	$	Requires careful dilution (1:20 ratio)
Vodka Method	Ethanol	Varies	$	Less effective carbon source, more algae control

Frequently Asked Questions

How long does it take to see results from Excel dosing?

Most aquarists notice improved plant pearling within 24-48 hours. Significant algae reduction typically takes 5-7 days of consistent dosing. For new tanks, it may take 2-3 weeks to see substantial plant growth improvements.

Can I use Excel with CO₂ injection?

Yes, but reduce your Excel dose by 30-50%. The combination can be particularly effective in high-light tanks where carbon demand is extreme. Monitor plant responses carefully as the combined carbon availability may lead to nutrient limitations elsewhere.

Why are my plants melting after starting Excel?

This typically occurs when:

• Dosing too high initially (start with 50% recommended dose)
• Using with sensitive plant species (like Vallisneria or some Cryptocoryne)
• Inadequate other nutrients (Excel increases carbon but plants need balanced fertilization)
• Poor water circulation distributing Excel unevenly

Reduce dose by 50% and ensure comprehensive fertilization (nitrates, phosphates, potassium, micronutrients).

Is Excel safe for shrimp?

Excel can be used with shrimp but requires careful dosing:

• Neocaridina shrimp: Maximum 0.5 mL/10G daily
• Caridina shrimp: Maximum 0.3 mL/10G daily
• Dose after water changes when glutaraldehyde levels are lowest
• Provide strong aeration to help break down glutaraldehyde
• Watch for signs of stress (rapid movement, loss of appetite)

Consider using shrimp-safe alternatives like USFWS-approved plant extracts if keeping sensitive shrimp species.

How should I store Excel?

To maintain potency:

• Store in original container at room temperature (60-75°F)
• Keep away from direct sunlight (UV degrades glutaraldehyde)
• Tightly seal the bottle after each use
• Use within 2 years of manufacture date
• Don’t refrigerate (condensation can dilute the product)

Conclusion and Final Recommendations

Excel dosing can transform your planted aquarium when used correctly. Remember these key points:

1. Start with conservative doses and increase gradually
2. Combine with comprehensive fertilization for best results
3. Monitor plant and livestock responses closely
4. Adjust based on seasonal changes in plant growth
5. Use our calculator regularly as your tank evolves
6. Consider spot treatment for stubborn algae issues
7. Maintain good water circulation for even distribution

For tanks with sensitive livestock or when first starting with Excel, we recommend beginning with 50% of the calculated dose for the first week, then gradually increasing to the full dose while observing tank inhabitants.

The most successful planted aquariums combine Excel dosing with proper lighting, CO₂ (when possible), and balanced fertilization. Use our calculator as a starting point, but always be prepared to adjust based on your specific tank’s response.