Don't buy the cheapest equipment. Buy the right outcome at the right total cost.

A common purchasing mistake

A typical pattern: a shrimp or fish farm compares two aeration or oxygenation offers on purchase price per unit. The cheaper offer lists fewer units or a lower rated oxygen transfer, assuming conditions that do not match the farm's peak biomass, night-time oxygen demand or water temperature.

After stocking, dissolved oxygen falls at night during peak biomass. Feeding is cut to protect the animals, growth slows, harvest weight drops and FCR rises. Additional units are bought in a hurry, often at a worse price and with downtime. The original saving disappears into lost survival, slower growth and higher cost per kg.

The root cause was not the manufacturer: it was comparing offers that were sized against different assumptions. One written design basis — biomass, feed load, oxygen demand, temperature and redundancy — would have made the two offers comparable.

Takeaway: a quote that is cheaper but undersized or incomplete is not cheaper — it moves cost into mortality, feed and downtime.

The 5-step buyer decision method

1. 1. Define the outcome

   Write the measurable result you need: survival, harvest size, growth rate, FCR, water-quality range and target cost per kg — with today's baseline.

2. 2. Fix the design basis and scope

   Species, biomass, feed load, oxygen demand, flow, temperature, redundancy and what is included: design, equipment, installation, commissioning, training, spares.

3. 3. Score offers with weights agreed in advance

   Use the scorecard below. Agree the weights internally before opening any offer.

4. 4. Check lifecycle cost and sensitivity

   Purchase price + installation + energy + maintenance + spares over the planning period, then test how cost per kg moves if FCR or survival change.

5. 5. Contract on acceptance tests and milestones

   Write the tests the equipment must pass and link payments to delivery, commissioning and proven performance.

Takeaway: decide the outcome and the scope before you compare prices.

Buyer scorecard (example weighting)

Score each offer 1–5 per criterion, multiply by the weight and add up. The weights below are an example to adapt to your project — not a standard.

Takeaway: weight criteria before you open the offers, so price cannot quietly decide everything.

Questions to ask every manufacturer

Our team puts the same questions to each manufacturer, so the answers can be compared line by line.

Takeaway: identical questions produce comparable answers.

Improve, expand or build new: the decision rule

Rule of thumb: fix the measured bottleneck first; expand only what already performs; build new only when the site or system cannot reach the target outcome.

Takeaway: buy new equipment only when the bottleneck is really the equipment.

Lifecycle cost check — try it here

Compare two offers over the same period. Enter your own numbers; the example values are placeholders, not supplier prices.

Illustrative calculation (example inputs, not prices)

Offer A costs USD 300,000 installed and USD 60,000 a year to run; offer B costs USD 360,000 installed and USD 40,000 a year. Over 8 years: A = 300,000 + 60,000 × 8 = USD 780,000; B = 360,000 + 40,000 × 8 = USD 680,000. The more expensive offer is USD 100,000 cheaper over the period and catches up after 3 years. Biology can matter even more: on 1,000 tonnes a year with feed at USD 1.10/kg, every 0.1 change in FCR changes feed cost by about USD 110,000 a year. Whether a given offer changes FCR or survival must be shown by trial data or written commitments — it is not assumed here.

Takeaway: compare lifecycle cost, not purchase price.

Related calculators and tools

Use these to build your design basis. Results are planning estimates to discuss with a qualified engineer or biologist.

• Oxygen requirement calculator

  Oxygen demand from daily feed — the basis for sizing aeration.

• Biofilter sizing calculator

  Ammonia load and biofilter capacity for RAS.

• RAS sizing calculator

  Tank volume and flow from target production.

• FCR calculator

  Convert feed records into FCR.

• Fish growth calculator

  Harvest weight and days to target size.

• Harvest profit calculator

  Revenue minus cost per cycle.

• 10-year TCO comparison (RAS, pond, cage, biofloc)
• RAS cost calculator (CAPEX/OPEX ranges)
• Why the cheapest quote can cost more (article)
• Outcome-first guide: define results before buying
• Fix, expand or build new? Decision framework

Payment terms and financing considerations

• Avoid paying most of the price at order. Link milestones to delivery, installation, commissioning and passed acceptance tests.
• Ask for a performance retention or bank guarantee where the contract value justifies it.
• Lenders look at cash flow and debt-service coverage; a lifecycle-cost comparison strengthens your loan file.
• Include working capital for the first cycles in the financing plan.
• FishMatch can introduce eligible projects to external financing partners. We do not lend, and approval is never guaranteed.

Takeaway: payment milestones are your strongest quality-control tool.

Key risks and acceptance tests

• ☐Factory acceptance test (FAT) for critical equipment before shipment, where practical
• ☐Site acceptance test under load: flow, pressure, power draw at duty point
• ☐Oxygen transfer or dissolved-oxygen performance at stated biomass and temperature
• ☐Power-failure and alarm test, including backup power start-up
• ☐Biofilter start-up and water-quality sign-off before stocking (RAS)
• ☐Controls handover, training, O&M manuals, as-built drawings and initial spares
• ☐Warranty start date and remedies written into the contract

Takeaway: if it is not tested at acceptance, it is not guaranteed.

Frequently asked questions

Sources and method

• Timmons & Ebeling — Recirculating Aquaculture (oxygen and biofilter design rules used by our calculators)
• FAO — The State of World Fisheries and Aquaculture 2024

Last reviewed: October 2026. Examples are arithmetic with stated inputs; no supplier prices or performance benchmarks are claimed.