Front Row pH Up Calculator

Always measure pH at the dripper or in the batch/bay tank. It is EXPECTED and NORMAL for pH readings to be LOW at the fertigation skid—especially in high flow situations. If testing in a batch tank, allow at least 10-15 minutes between pH adjustment and checking values.

This calculator provides pH Up dosing recommendations based on your recipe and target EC. It's built on regression equations generated from 131 real-world data points, giving you precise starting points for dialing in your pH. All recommendations target a final pH of 5.9.

Important: RO water only. These recommendations assume you're starting with RO water. If your source water has alkalinity (tap water, well water), you will need less pH Up than shown. Using the full recommended amount with alkaline source water will cause problems.

Features:

• Preset buttons: Quick-fill for High Strength or Standard feed chart ECs, or enter custom values.
• Output formats: View results in g/gal, mL/gal, or % injection rate.
• Share Link: The URL updates as you make changes—copy and send to share your exact configuration.
• Copy Summary: Get a formatted text version of your settings and recommendations.

For commercial and home growers alike, whether mixing direct to reservoir or running stock concentrate through an injection system.

As RO membranes age and approach their replacement threshold, they allow more carbonate and alkalinity to pass through. This gradually raises the natural buffering capacity of your source water — a phenomenon called alkalinity creep.

The practical effect: your pH Up demand drops over time without any change to your feed recipe. If you notice you're using less pH Up than usual, your membranes may be degrading.

What to do: You can lower your standing pH target slightly as membranes age to account for the extra alkalinity passing through. When membranes are eventually replaced, pH Up demand will jump back up to baseline — so recalculate after any membrane change.