HUSBANDRY · CONTROLLED DOCUMENT
AE-SOP-0120 — RO & Reservoir Water Preparation
To produce, condition, and store the reverse-osmosis and mixing-reservoir water on which every holding system depends, so that no exchange ever draws water that is off-spec. The procedure guarantees that RO product water meets purity limits before it enters a reservoir, that each reservoir is matched to its destination zone and aged before use, and that production stays ahead of demand — because a station that runs its reservoirs dry has no answer to a water-quality fault.
ActiveHusbandryRev C
Doc Control AE-SOP-0120Revision CEffective 2090-04-10Next Review 2091-04-10Owner Engineering Dept.Approver Marine ScienceStatus ActiveClass RESTRICTED // TIDEWATER-EYES-ONLY
1. Purpose
To produce, condition, and store the reverse-osmosis and mixing-reservoir water on which every holding system depends, so that no exchange ever draws water that is off-spec. The procedure guarantees that RO product water meets purity limits before it enters a reservoir, that each reservoir is matched to its destination zone and aged before use, and that production stays ahead of demand — because a station that runs its reservoirs dry has no answer to a water-quality fault.
2. Scope
All RO production and mixing-reservoir conditioning feeding the holding systems.
- In scope: Membrane production, product-water purity verification, salt and buffer dosing, reservoir aging, and level management.
- Out of scope: The exchange decisions that draw from the reservoirs, which follow AE-SOP-0112; emergency reservoir draw during life-support failure, which follows AE-SOP-0211.
3. Definitions
| Term | Definition |
|---|
| Product Water | The permeate from the RO membranes, held off-line until purity is verified within limits. |
| Mixing Reservoir | A conditioned, zone-matched water store aged before it is released for exchanges. |
| Aging | The minimum equilibration time a freshly dosed reservoir holds before use, for stable chemistry. |
| Reject Ratio | The fraction of feed water sent to brine reject, a health indicator for the membranes. |
| Make-Up Margin | The reserve of prepared water held above forecast demand so production never falls behind. |
4. Responsibilities
| Role | Responsibility |
|---|
| Engineering Dept. (Owner) | Owns RO production and membrane maintenance; signs reservoir release to service. |
| Water-Prep Operator | Runs production, doses salts and buffers, and verifies purity before reservoir fill. |
| Marine Science | Sets per-zone target chemistry and buffer specification for each reservoir class. |
| NEREID | Forecasts reservoir demand against production rate and flags any store falling below the make-up margin. |
5. Reservoir Preparation Specification
| Reservoir Class | Target Salinity | Buffer / pH | Minimum Aging |
|---|
| RO product (pre-dose) | 0 ppt | TDS < 10 mg/L | Hold to purity pass |
| Tropical reef mix | 34–35 ppt | pH 8.2 ± 0.1 | ≥ 24 h |
| Cold-water / temperate mix | 32–34 ppt | pH 8.0 ± 0.1 | ≥ 24 h |
| Freshwater conditioned | 0 ppt | pH 7.0 ± 0.3 | ≥ 12 h |
Note. No reservoir is released for service before its aging time and a purity pass; freshly dosed water is never sent straight to a holding system, because unstable chemistry shocks livestock harder than a small drift would.
6. Materials & Equipment
- Multi-stage RO membrane train with product and reject metering
- Calibrated TDS, conductivity, and pH instrumentation
- Reef and freshwater salt mixes and buffer stock
- Zone-matched mixing reservoirs with level sensors
- Recirculation and aging mixers
- Membrane maintenance and flush kit
7. Procedure
7.1 Production
- Run the RO train and meter product water against the reject ratio.
- Hold product water off-line until TDS and purity pass the spec.
- Flag any membrane whose reject ratio drifts from baseline for maintenance.
7.2 Conditioning
- Dose salts and buffer to the destination-zone target for the reservoir class.
- Recirculate and age the reservoir for at least its minimum aging time.
- Verify salinity, pH, and temperature in band before release.
7.3 Service & Reserve
- Release the aged, in-spec reservoir to service on Engineering sign-off.
- Hold prepared water above the forecast make-up margin at all times.
- Schedule production to refill any store trending below margin before it is needed.
8. Records
- RO production log with product purity and reject ratio (retained 2 years)
- Reservoir dosing and aging record per batch
- Pre-release chemistry verification
- Membrane maintenance and flush log
- Reservoir level and make-up-margin trend
9. References
10. Revision History
| Rev | Date | Author | Summary |
|---|
| A | 2088-02-11 | Engineering Dept. | Initial issue; RO purity verification and reservoir aging established. |
| B | 2089-06-05 | Engineering Dept. | Added per-zone reservoir classes and buffer specification. |
| C | 2090-04-10 | Engineering Dept. | NEREID demand forecasting and make-up-margin reserve formalised. |