How to Carry Out a Water Change on Your Lobster Tank
Maintaining optimal water quality is essential for the health and vitality of your lobsters. One of the key maintenance tasks in operating a Lobster Pod system or any lobster tank is performing regular water changes. Once your system is fully matured, we recommend a water change of around 20% every four to six weeks. Here’s a step-by-step guide to how we do it—and how you can too.
Why Water Changes Matter
Over time, nitrogen waste in the system breaks down into nitrate. While nitrate is the least toxic form of nitrogen, excessive levels—especially above 250 mg/L (or 250 ppm)—can be harmful to shellfish. Water changes help control these levels, ensuring a clean and stable environment for your lobsters.
In mature systems, a gradual increase in nitrate is normal. However, maintaining regular water changes is the most effective way to prevent nitrate build-up and maintain system balance.
When to Change the Water
- Routine Maintenance: Every 4 to 6 weeks (20% change)
- During Maturation: More frequent changes may be required during the first 6 weeks
- High Nitrate Levels: Perform a change if nitrate exceeds 250 mg/L
- Customer Preference: Some users opt for a full 100% change monthly
Your decision between a 20% or full change will depend on your system’s condition, stocking density, and your water quality results.
Step-by-Step Water Change Process
- Switch Off the System
Start by turning off the system and allowing the trays to drain into the sump. - Access and Clean the Filters
Remove the bottom two trays to access the foams. Take out the foam pads and the plastic shelf. - Drain the Water
Insert a submersible pump into the sump and pump out the desired amount of water into a drain. For a 20% change, calculate the system’s total volume and remove the appropriate portion. For a full water change, drain the entire sump. - Clean Additional Filter Parts
While the water is out, it’s a good opportunity to rinse sponges or clean any other filter components. - Prepare Your Seawater
- Natural Seawater: If you’re using fresh seawater, simply pump it in once drained.
- Artificial Saltwater: If mixing your own, prepare it at least 24 hours in advance in a tank or IBC. Use a dechlorinator on tap water before adding salt, and ensure the salinity matches your existing system—especially if lobsters are still in the Pod.
- Refill the System
You can pump the new water into the sump, directly into the filter, or via a removed filter sock.
Salinity Matching: A Vital Step
If lobsters are still in the system during the water change, salinity matching is critical. Sudden shifts—even to cleaner water—can cause stress. Always verify salinity before introducing new artificial seawater.
Monitoring and Support
During the system’s maturation phase, it’s important to test water quality frequently and gradually introduce stock. Overloading too early can stress both the system and your lobsters. If you’re unsure about timing, water volume, or test results, we’re here to help—just get in touch.
Final Thoughts
Water changes are a simple yet vital part of maintaining a healthy Lobster Pod. Whether you choose a partial or full change, consistency is key. Keep an eye on nitrate levels, follow the steps above, and your system will reward you with a stable and thriving environment.
For more information or advice please get in touch with our Research & Development Director, marine biologist Dr Keith Todd on Tel +44 1383 820685 or Email hello@toddfishtech.com
