Deep Maintenance & Check Valve Fix

• Performed an extensive maintenance session focused on filtration, flow, and system reliability.
• Completed a near-total sump drain (~100%) and a reduced ~50% display water change to avoid over-stressing the system during heavy maintenance.
• 🔧 Filtration & Cleaning
  • Rinsed coarse and medium sponges in the filter stack
  • Rinsed pre-return sponge/filter due to clogging
  • Removed spent Purigen (replacement needed)
• Due to the level of cleaning (including tap water exposure), Stability was dosed to support bacterial recovery. Prime was also dosed during refill as usual.

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• ⚙️ Mechanical Fix — Overflow Issue
  • Check valve in return line was stuck open due to debris
  • Disassembled and cleaned the valve
  • Restored proper function (pending confirmation under test)
• This was likely allowing unintended backflow, causing sump overfill during shutdown events.
• The longer DIY sump lessons explain what the check valve taught me.

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• 🌱 Plant Management
  • Planned trimming of tiger lotus postponed to avoid stacking stress with major maintenance
  • System showing strong plant growth despite reduced bioload

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• 🧪 Forward Plan (System Experiment)
  • Replace nitrate test kit
  • Begin observing natural nitrate accumulation under current lower bioload
  • Potential shift toward:
    • Nitrate-driven water changes instead of fixed schedule
    • Smaller display changes (~25% or less) while maintaining sump maintenance

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• 📌 System Status
  • Bioload reduced compared to previous months
  • Plant growth accelerating
  • Filtration refreshed
  • Mechanical reliability improved (pending validation)
• System entering a “controlled observation phase.”