Rowaphos Calculator

RowaPhos Dosage Calculator

Liters US Gallons

Seawater (Marine) Freshwater

Recommended Amount:

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Understanding RowaPhos Dosage for Aquariums

RowaPhos is a high-capacity Granular Ferric Hydroxide (GFO) used by aquarium enthusiasts to remove phosphates and silicates from marine and freshwater environments. Managing phosphate levels is critical for preventing nuisance algae growth and ensuring the health of stony corals (SPS), which can experience stunted growth or tissue loss in high-phosphate water.

How This Calculator Works

The amount of RowaPhos required depends on three main factors: your total water volume, the type of water (salt vs. fresh), and the current phosphate concentration. Our calculator uses the official manufacturer recommendations as a baseline:

• Maintenance Dose (Seawater): 100ml (approx. 100g) treats 400 liters if PO4 is under 0.5ppm.
• Initial High-Load Dose (Seawater): 100ml (approx. 100g) treats 200 liters if PO4 is above 0.5ppm.
• Freshwater Dose: Since freshwater holds less ionic interference, 100ml generally treats 800 liters for maintenance.

Dosage Examples

To provide context for your calculations, consider these common scenarios:

Tank Size	Water Type	PO4 Level	Recommended Rowa
100 Gallons	Seawater	0.10 ppm	95 grams
200 Liters	Seawater	1.00 ppm	100 grams
50 Gallons	Freshwater	0.40 ppm	24 grams

Best Practices for Using RowaPhos

1. Do Not Over-tumble: If using a media reactor, RowaPhos should only slightly "simmer" at the surface. Aggressive tumbling will cause the media to grind into fine dust and enter the display tank.

2. Rinsing: It is often recommended to rinse the media with a small amount of RO/DI water or aquarium water to remove fines before use, although some users prefer not to rinse to avoid losing capacity.

3. Testing: Test your phosphate levels weekly. When the PO4 levels stop dropping or start to rise again, it is time to replace the media.

4. Stability is Key: In reef tanks, do not drop phosphates from high levels (e.g., 2.0 ppm) to near zero in a single day. This can shock corals. Use smaller amounts of RowaPhos and change them more frequently to achieve a gradual decline.

function calculateRowaphos() { var tankVolume = parseFloat(document.getElementById('tankVolume').value); var volumeUnit = document.getElementById('volumeUnit').value; var waterType = document.getElementById('waterType').value; var currentPO4 = parseFloat(document.getElementById('currentPO4').value); var resultsArea = document.getElementById('resultsArea'); var gramResult = document.getElementById('gramResult'); var dosageNote = document.getElementById('dosageNote'); if (isNaN(tankVolume) || tankVolume 0.5) { // High load seawater: 100g per 200L gramsRequired = liters * (100 / 200); doseType = "High Load Initial Dosage"; } else { // Maintenance seawater: 100g per 400L gramsRequired = liters * (100 / 400); doseType = "Standard Maintenance Dosage"; } } else { // Freshwater logic if (currentPO4 > 0.5) { // High load freshwater: 100g per 400L gramsRequired = liters * (100 / 400); doseType = "High Load Initial Dosage (Freshwater)"; } else { // Maintenance freshwater: 100g per 800L gramsRequired = liters * (100 / 800); doseType = "Standard Maintenance Dosage (Freshwater)"; } } // Rounding for practicality var finalGrams = Math.ceil(gramsRequired); var approxVolumeMl = finalGrams; // RowaPhos is roughly 1g = 1ml resultsArea.style.display = 'block'; gramResult.innerHTML = finalGrams + " grams (" + approxVolumeMl + " ml)"; dosageNote.innerHTML = "Based on a " + doseType + " strategy for a " + tankVolume + " " + volumeUnit + " system."; }