This classification mainly includes the aluminum low-pressure casting Machinery Parts using in auto area. Low-Pressure Casting Auto Part,A356 Low-Pressure Casting Parts,ZL101A Low-Pressure Casting Parts NINGBO ZHENHAI BOLANG METAL PRODUCTS FACTORY , https://www.casting-part.com
From the part, we can easily find that the parts have a lot of features of big cavities, so the part will have big potential risk of mold release problem, if so, the part may happen to be deform, sticking to the mold etc, especially when the part sticking to the mold, if no clear in time, while next shot, the mold may be destroyed while clamping.
Normal raw material: A356.ZL101A.ZL101.AlSi7Mg
Process Technology: Low-pressure casting,T6 Treatment,Shot Blasting,NC Machining,Spray Coating
Product Dimensions: Customized
Casting General Tolerance: Grade GBT6414-CT8
Flow Processes: Die casting, Degating to remove the residual of the gate, Polishing and Deburring to remove the burrs, Polishing to remove the parting line, flash,CNC Turning, Cleaning, Packaging, Storaging, Shipping
Control Measure: Incoming Material Test, First Article inspection, Routing inspection, Final item inspection, and Outgoing quality control
Inspection Equipment: CMM, Caliper, Plug Gage, Screw Gauge
Application: Machinery Parts
Certificate: IATF16949:2016,ISO14001:2015,ISO45001:2018
Lead Time: 30-35 days
Trade Term: FOB Ningbo
How to Control the Water Quality of Shrimp Nursery
Nursery Water Quality Requirements
During the nursery phase, maintaining optimal water quality is crucial for the health and survival of shrimp larvae. The water should consistently meet specific standards: a pH range of 7.8 to 8.4, chemical oxygen demand (COD) below 1 mg/L, total ammonia nitrogen under 0.05 mg/L, nitrite nitrogen less than 0.01 mg/L, and dissolved oxygen above 5.0 mg/L. The source water should ideally have a COD level below 1 mg/L, while the pond water should not exceed 5 mg/L. Salinity should be maintained between 25-32 during the nauplii to shrimp stage, with adjustments made as needed. Proper water management is essential, and although detailed guidelines exist elsewhere, this article focuses on key practices.
Optimal Larval Density and Feeding
Overstocking is a common issue in many shrimp farms, which can lead to poor water quality and lower survival rates. Adjusting the density based on species and life stage is critical. For example, nauplii should be kept at around 100,000 per liter, while Penaeus vannamei larvae should be limited to about 150,000 per liter. Feeding must also be carefully managed to ensure adequate nutrition without overfeeding, which can degrade water quality. In general, artificial feed should be provided 6 times daily, with amounts ranging from 0.5–1.2 g/m³ in early stages and increasing to 1.2–2.5 g/m³ during later phases. Artemia nauplii should be fed 6–20 times per day depending on the developmental stage. Adjustments should be made based on larval behavior and water conditions to avoid waste and maintain a healthy environment.
Feeding with Single-Celled Algae
Single-celled algae play a vital role in improving shrimp vitality and reducing disease outbreaks. During the zoea stage, their absence can lead to low survival and delayed metamorphosis. Feeding the right amount of algae—such as Skeletonema or Chaetoceros—at appropriate concentrations (10–15 cells/mL) helps maintain water stability. However, overfeeding can cause algal die-off, worsening water quality. It's important to select live algae with no dead cells and to monitor the color and activity of the culture. After P5, algae feeding should be reduced or stopped to prevent unnecessary organic load.
Preventing Contamination
Contamination can occur from various sources, including self-contamination from larvae, acid rain, sand filters, and surrounding pests. To reduce risk, larvae should be disinfected before entering the nursery using formalin or iodine solutions. Acid rain can disrupt the water balance, so immediate water changes and additives like water improvers are necessary. Sand filters and filter bags should be cleaned regularly to prevent the buildup of harmful organisms. Additionally, pest control measures such as fumigation and insecticides are essential to keep mice, cockroaches, and birds away from the nursery area.
Water Changes and Disinfection
Regular water changes are one of the most effective ways to maintain water quality. When pH levels, ammonia, or nitrite levels become too high, or when signs of disease appear, water should be changed promptly. A typical practice involves adding 20 cm of new water each time, changing it 1–2 times with 20–40% replacement, or 1–3 times with 30–60% replacement. Disinfectants like potassium permanganate, formaldehyde, and chlorine dioxide can also be used to improve the microbial environment and reduce pathogen load.
Use of Beneficial Microbes
Beneficial microorganisms are widely used to enhance water quality by breaking down organic matter, reducing harmful substances, and promoting a balanced ecosystem. These agents can be added directly to the water at a dosage of 3–10 ml/m³, depending on the product instructions. Their use has been shown to improve survival rates and reduce disease incidence in shrimp nurseries.