Reservoir maintenance

Remove the soil before you sanitize the system.

Cleaning and sanitizing are separate steps. Cleaning removes plant debris, deposits, algae, and biofilm so a compatible sanitizer can contact the surface. A change-out replaces nutrient solution; it does not automatically clean hidden lines, pumps, trays, or tools.

During-crop maintenance is bounded

Keep the area orderly, remove dead plant material, verify flow, protect the reservoir from unintended light, and inspect accessible surfaces. Do not improvise a strong cleaning or sanitizer treatment around living roots. University of Minnesota Extension specifically separates in-crop maintenance from the more complete between-crop process.

If a reservoir needs replacement during a crop, document the reason, current readings, water source, and products. Use clean tools and avoid splashing nutrient solution onto edible plant parts.

Between crops allows full access

Disconnect electrical equipment safely, drain under local disposal rules, disassemble the parts the manufacturer permits, and remove roots and debris. Clean reservoir walls, trays, channels, tubing, pump surfaces, net pots, and other water-contact components.

Inspect wear, seals, impellers, lines, and air stones. Replace damaged parts rather than sanitizing them and assuming function is restored.

A controlled clean-and-sanitize sequence

Plan the shutdown, protect the crop if present, isolate power, and wear the protective equipment required by equipment and chemical labels.
Drain responsibly. Nutrient solution contains fertilizer; do not assume a household drain or stormwater path is acceptable.
Remove roots, leaves, sediment, algae, and other visible material. Disassemble only what the equipment manual allows.
Wash surfaces with a compatible detergent, water, and suitable brush. Mechanical cleaning breaks up material and biofilm that can shelter microorganisms.
Rinse away loosened material and detergent as directed.
Apply a sanitizer approved for the surface and intended use. Follow its exact concentration, contact time, temperature, ventilation, PPE, rinse, and disposal label.
Air-dry or reassemble as directed. Flush lines when required, restore clean source water, verify leaks and flow, then prepare a documented fresh nutrient mix.

Do not mix cleaning chemicals

Combining bleach, acids, ammonia products, peroxide products, or other cleaners can create dangerous reactions. Use one approved process, maintain labeled containers, and follow the safety data and product label. Never use a nutrient calculator to determine sanitizer concentration.

The University of Minnesota guidance provides example procedures for its described systems, but a specific sanitizer label and equipment compatibility remain authoritative. More chemical is not automatically more effective.

Find the physical cause of repeat buildup

Repeated algae or biofilm can point to light leaks, warm stagnant areas, debris, inadequate flow, difficult-to-clean materials, or inconsistent maintenance. Mineral scale can relate to source-water hardness and concentration. Inspect causes using temperature, circulation, and oxygen guidance and the source-water guide.

Remeasure flow, temperature, EC, and pH after the cleaned system is refilled and circulating. Meter cleanliness matters too; do not reintroduce residue with an unmaintained probe.

Decide when the solution itself needs replacement

Crop cycle, system design, water quality, solution age, selective uptake, plant condition, and correction history all matter. Extension schedules are useful references, but they are not proof that every reservoir needs the same calendar.

If the mix is old, layered with corrections, contaminated, precipitated, or no longer understandable, use the top off, dilute, or remix guide rather than forcing EC back to target.

Restart with a documented baseline

After cleaning, verify the actual working volume, source water, product versions, recipe, measuring tools, and mixing order. Dissolve products separately as required, circulate, and take stable meter readings.

Record the fresh-mix date and response. That baseline makes later EC and water-level changes more interpretable using the reservoir trend guide.

Use calculations only for a known, mixed reservoir

YieldPivot estimates nutrient and pH adjustments; it does not select sanitizers or certify sanitation. Once the system is safely clean, filled, mixed, circulating, and measured, use the correct product or recipe, add in stages, circulate, remeasure, and recalculate.

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Sources and limits

This page intentionally does not provide a universal sanitizer dose. Product formulation, surface, food-contact status, system materials, crop presence, local rules, and labels vary. Follow current equipment and chemical instructions and seek qualified safety guidance when the correct process is uncertain.