Water Change Journal Keep a sequence of planned and performed water changes, compare nitrate dilution estimates with actual after-tests and preserve the assumptions behind the plan. 1. Open Tools and Water Change Journal. Verify net water volume, starting nitrate reading and its date. 2. Add changes with replacement volume and source-water nitrate. Mark a change performed only after doing it, and add an optional actual after-test. 3. Review the chart and sequence, save the journal and share the record. Dilution assumes uniform mixing and no new nitrate production or removal between steps. It is a planning estimate, not a recommendation about a safe change size. Actual after-tests become the next starting value. Use measured net volume. Up to 12 changes per journal and 100 journals. pH is no longer offered as a linear dilution calculation.

This update sharpens the interface: the iPad layout now uses a centered, comfortable reading width instead of stretching edge to edge, plus small display fixes. iPhone is unchanged; still fully on-device.

Gillwise 2.0 — a big pro upgrade from a water grader to a full tank-management suite, still 100% offline. • New Tools tab gathers every calculator: • Dosing calculator for dechlorinator, marine salt mix, and dry-salt fertilizer ppm by tank volume. • Equipment Sizer: heater wattage from your temperature rise and filter turnover GPH. • Tank Volume & Surface for five shapes, with water weight and a "create tank" shortcut. • CO₂ calculator from pH and KH with a target-zone verdict. • Acclimation Timer with a live float/drip countdown and haptics. • A surface-area stocking metric alongside bioload, plus a shareable PDF tank report. All aquarium math is computed on-device and verified. Advice is informational, not veterinary. No account, no network — everything stays on your device.

Version 1.1 - Parameter history chart - see any of your 9 logged parameters (pH, ammonia, nitrite, nitrate, temperature, GH, KH, salinity, phosphate) on a real line chart. Choose 7-day, 30-day, 90-day, or all-time windows. Min, max, and latest stats shown beneath the chart. - Nitrogen Cycle Tracker - for new tanks under 6 weeks old, Gillwise reads your ammonia, nitrite and nitrate history and tells you which phase you're in: Ammonia Spike, Nitrite Spike, or Cycled. Plain-English guidance for what to do next at every stage. - Smart test pre-fill - opening "Log water test" now pre-fills every field from your most recent reading. Just update the values that changed.