Saltwater changes the materials and the stages.
Seawater corrodes metal, foams readily and starts biofilters slowly. Ozone behaves differently too. We design marine and brackish systems around those four facts. We have not yet delivered a marine fish farm, and we say so up front.
no marine fish farm yet
shrimp farms delivered
metal matched to salinity
standard in seawater
We have not delivered a marine fish farm yet. Our shrimp projects, our seawater equipment and published research inform this design.Engineering basis.
Four things a freshwater design gets wrong.
Corrosion
Stainless grades that last in freshwater can pit in seawater
PP and UPVC bodies; wetted metal matched to salinity, stepping up to duplex stainless
Foam
Protein foam forms readily
Protein skimmer as a standard stage
Ozone chemistry
Ozone reacts with bromide to form longer-lasting oxidants and bromate
Ozone dosed on feed in the skimmer; residual oxidant measured before water returns
المرشح البيولوجي
Nitrifying bacteria start more slowly and work at lower rates
More media; a longer, staged start-up planned into the schedule
The dose that works, and the dose that does not.
In a commercial seawater RAS, ozone at 7 g per kg of feed with foam fractionation gave good water quality. At 14 g/kg, residual oxidant in the water rose, which is the risk to fish and biofilter (). More ozone is not better; the dose is set on feed and checked against residual oxidant.Aquacultural Engineering, 2023
- on side-stream flow and feedSkimmer sized
- in the skimmer, on feedOzone dosed
- measured before water returns to the tanksResidual oxidant
- vented and destroyed, away from peopleالغازات الخارجة
Salinity sets the design.
مياه قليلة الملوحة
Shrimp; some marine fish nurseries
Most seawater rules apply; materials confirmed per salinity
Full seawater
Marine fish; post-smolt
Duplex or non-metal wetted parts; skimmer; ozone with oxidant control; slow start-up
Seawater made up from salt
Inland sites
Salt cost makes low water exchange important; make-up water treated before use
Units we supply for marine systems.
PP tanks and drum filters
مزيلات البروتين
معقمات الأشعة فوق البنفسجية
When a seawater system goes wrong.
Rust stains or pitting on fittings
Metal grade not suited to seawater
Wetted metal parts; replace with a suitable grade
Fish stressed after ozone is raised
Residual oxidant reaching the tanks
Oxidant reading; ozone dose
Nitrite stays high for weeks after start-up
Slow marine nitrification
Start-up plan; stock in smaller steps
Skimmer overflows with wet foam
Air or water flow too high, or a sudden load
Skimmer air and water settings
Our salt and brackish water experience: shrimp.
1,200 m³ shrimp and bass RAS, Fangcaohu
Not yet. We say so in every proposal. Our delivered shrimp farms and seawater equipment inform the design.
PP and UPVC bodies where possible. Metal parts in contact with water are chosen for the salinity; in seawater the industry steps up to duplex stainless. We confirm each wetted part per order.
Many marine systems pair ozone with protein skimmers. In one commercial seawater RAS, 7 g ozone per kg of feed worked well and 14 g/kg raised residual oxidant. We set the dose on feed.
With control, yes. In seawater ozone forms bromine oxidants and bromate, which last longer than ozone. Residual oxidant is measured before water returns to the fish.
Marine nitrifying bacteria establish more slowly. We plan a longer start-up and staged stocking.
Yes, with made-up seawater. Low water exchange keeps salt cost down, which raises the importance of every treatment stage.
Send species and water. We share the engineering basis.
Send species, target output and site size. A first layout comes back in 3 days, free.
- Clear about what is not yet delivered
- Seawater materials
- Skimming, ozone and oxidant control
- No obligation to order