Guide to Culturing Phytoplankton

 

Beginner's Guide to Growing Phytoplankton

What You'll Need

- Clean container
- Air pump with tubing
- Aquarium light
- Starter culture (arrives in a 250ml pouch)
- Salt water mix
- Reefphyto nutrients/fertiliser for phytoplankton
- Clean measuring spoons or cups
- Timer for your light

Step 1: Clean Everything

1. Wash your container with warm, soapy water
2. Rinse it really well - no soap should remain
3. Let it air dry or use a clean paper towel

Step 2: Set Up Your Bubbler

1. 1. Put your air pump on a surface higher than your container
   2. Connect the air tube to the pump
   3. Place the other end in your container
   4. The bubbles should be gentle - like a soft drink, not a hot tub!

Step 3: Make Your Salt Water

1. Use aquarium salt mix and ro water
2. You want it about as salty as the ocean (aim for 1.025)

Step 4: Start Your Culture

Fill your container about 2/3 full with your salt water
2. Add your starter culture (the green liquid you bought)
3. Add 6ml of Reefphyto Nutrient Guillard's F/2 food. This initial double concentration helps kickstart the culture. Avoid further fertilisation during the first growth cycle. Top up your container with salt water.

Step 5: Light and Temperature

1. Place your container where it's:
   - Not in direct sunlight
   - Room temperature (20-27°C is perfect)
   - Near your light source
2. Set your light timer for 16 hours on, 8 hours off

If you would like to know which lighting is best for growing phytoplankton, please see our guide here on our website

Taking Care of Your Culture

Daily Check

- Make sure the water is bubbling
- Check that the light is working
- Look at the color - it should be green, not brown or cloudy

What to Expect

- Days 1-3: Not much change
- Days 4-7: Getting greener
- Days 8-10: Should be a darker green

When It's Ready

- The water should look a darker green
- This usually takes about 10 days
- No bad smells (should smell like the ocean)

Harvesting Your Phytoplankton

When to Harvest

- Wait until the culture is dark green
- Usually around day 10-12
- The liquid should be uniformly green

How to Harvest

1. Save about 1/3 of your culture in a clean container
2. Use the rest for your aquarium
3. Add new salt water and nutrients to your saved portion
4. This becomes your starter for the next batch

Common Problems and Solutions

Culture Isn't Getting Green

- Check if your light is close enough
- Make sure you added nutrients
- Verify the bubbler is working
- Temperature might be too high or low (ideal is 20-27°C)

Bad Smell

- If it smells bad, start over
- Clean everything extra well
- Make fresh salt water
- Use new starter culture

Water Is Cloudy (Not Green)

- Probably contaminated
- Start fresh with a clean container
- Make sure all equipment is very clean

Tips for Success

- Patience! It takes time to get a dark green colour
- Keep everything clean
- Don't place in direct sunlight
- Use clean containers for harvesting

When to Start Over

- If the culture smells bad
- If it turns brown, grey or yellow
- If it's been more than 3 weeks

Remember: Your first try might not be perfect, and that's okay! Each culture helps you learn more about growing phytoplankton.

Need help? Take a photo of your culture if something seems wrong - most problems can be identified by looking at the colour and clarity of the water.

Happy Growing! 🌊