Softwash Mix Calculator

Softwash Mix Ratio Calculator

Professional-grade batch calculation for Sodium Hypochlorite (SH) and Surfactant mixes.

Required Mix Components:

Sodium Hypochlorite (Bleach): 0 Gallons

Water: 0 Gallons

Surfactant (Soap): 0 Ounces

function calculateSoftwash() { var batchSize = parseFloat(document.getElementById('batchSize').value); var shStrength = parseFloat(document.getElementById('shStrength').value); var targetMix = parseFloat(document.getElementById('targetMix').value); var surfactantRate = parseFloat(document.getElementById('surfactantRate').value); if (isNaN(batchSize) || isNaN(shStrength) || isNaN(targetMix) || isNaN(surfactantRate)) { alert('Please enter valid numeric values.'); return; } if (targetMix > shStrength) { alert('Target strength cannot be higher than source chemical strength.'); return; } // Logic: SH Needed = (Target % / Source %) * Total Batch Size var shRequired = (targetMix / shStrength) * batchSize; var waterRequired = batchSize – shRequired; var totalSurfactant = batchSize * surfactantRate; document.getElementById('shOutput').innerText = shRequired.toFixed(2) + ' Gallons'; document.getElementById('waterOutput').innerText = waterRequired.toFixed(2) + ' Gallons'; document.getElementById('soapOutput').innerText = totalSurfactant.toFixed(2) + ' Ounces'; document.getElementById('swResult').style.display = 'block'; }

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How to Calculate Your Softwash Mix Ratio

Achieving the perfect chemical balance is critical for softwashing. Too weak, and you won't kill the organic growth (mold, algae, lichen); too strong, and you risk damaging the property's surfaces or landscaping. This calculator helps you determine the exact volume of Sodium Hypochlorite (SH) and water needed to reach your target concentration.

Common Target Strength Recommendations

Depending on the surface you are cleaning, your target mix percentage will vary significantly:

• Siding (Vinyl/Stucco): 0.5% to 1.5% SH strength. Usually enough to kill green algae without harming paint.
• Concrete/Flatwork: 2.0% to 3.0% SH strength. Required for heavy organic buildup on porous surfaces.
• Roofs (Asphalt Shingles): 3.0% to 4.0% SH strength. Gloeocapsa Magma (black streaks) requires a higher concentration to ensure a complete kill.

The Math Behind the Mix

The formula for batch mixing is based on the volume-to-concentration ratio. To find the amount of SH needed, we use:

(Target Strength % ÷ Source SH Strength %) × Total Batch Size = Gallons of SH Required

For example, if you want a 50-gallon batch at 3% strength and you are using 12.5% pool chlorine:

• 3 / 12.5 = 0.24
• 0.24 × 50 = 12 Gallons of SH
• 50 – 12 = 38 Gallons of Water

The Role of Surfactants

Surfactants (soap) are non-negotiable in softwashing. They serve three main purposes:

1. Cling Time: Keeps the chemical on vertical surfaces longer so it can work.
2. Surface Tension: Helps the mix penetrate the pores of the substrate.
3. Scent Masking: Reduces the harsh smell of bleach for the customer.

Most professional surfactants are concentrated and only require 1 to 2 ounces per gallon of the final mix.

Safety Precautions

Pro Tip: Always add your chemical to water, not water to chemical, to prevent splashing. Wear appropriate PPE including gloves, eye protection, and a respirator when handling concentrated Sodium Hypochlorite. Ensure all vegetation is pre-wet and post-rinsed to prevent plant damage.