I wanted to build a second copepod culture vessel, so thought I would write a quick post giving step by step instructions on how to DIY your own culture vessel. As per my original post how to culture your own copepods, here is your shopping list:
lidded plastic box (H:190mm, W:260mm & D: 365mm)
rigid & flexible air line + flow valve
two cable glands (M20 x 1.5cm)
sea water (RO water + sea salt)
You will also need a drill and a 20mm core cutting drill bit.
Culture vessel. Your culture vessel can be anything from a small aquarium to a plastic or Tupperware container that holds enough water. I use white plastic lidded boxes for my culture vessel. Dimensions are Height:190mm, Width:260mm & Depth: 365mm. The lid helps reduce evaporation.
The box needs to be slightly adapted with two 20mm diameter holes to fit the (M20 x 1.5mm) cable glands. Carefully drill both holes using a 20mm core cutting drill bit. The first is drilled in one side near the top above your proposed water line to fit the air line. The second is drilled in the lid to fit the airlock.
Fit the cable glands to the two holes.
Connect the rigid airline (RO hose) to the flow valve, insert it through the gland on the side of the box ensuring that the airline in on the inside of the box and tighten to secure.
Insert the brewers airlock into the gland on the lid and tighten off to attached it securely.
Air pump & flexible hose. The flexible air hose is attached to your air pump. Cut to length the flexible airline, so it runs from your pump to your box with a little slack. Attach one end to the air pump, and the other to the flow valve on the side of the culture vessel.
Culture water. Fresh seawater (RO water & sea salt) to fill your culture vessel. The suggested specific gravity is usually around 1.020 SG. The salinity of my copepod culture water matches my reef tank (1.025 SG, 35 PPT). As said in my original post on culturing copepods, I’m working on the theory this reduces shock and increasing survival rates when copepods are added to your main tank. I make up a batch of 2o litres of sea water at a time for 10% weekly water change and rinsing the harvested copepods.
Fill your container with the seawater, no more than about two-thirds full and mark the outside of the culture vessel with a permanent marker line level with the top of the internal water line.
The line helps with
- harvesting the copepods – you simply top up the water with new seawater as necessary,
- enables weekly water changes – easy to replenish the culture tank with new seawater to replace the water removed. I aim for about 10% which is a litre.
- ensures you see any evaporation between harvesting / water changes and top up with RO water as necessary. Any evaporation of water ( water will be below your water level mark) should be replaced with RO not sea water – as this will effect the salinity of your copepod culture and may cause it to crash. Top up with RO until your culture water returns to your water level mark.
Turn on the air pump and adjust flow until you only have a slow bubble rate, roughly one bubble per 1-2 seconds.
Add Copepod feed. To begin with add a very small amount of copepod feed to lightly colour the culture water until you copepods multiply. Do not add too much or the water will foul and the culture will probably crash.
Add live copepods. Your set up is now good to go, so add your copepods and place the lid on.
Over the next few weeks, your copepods will reproduce and once they get to a certain population level you will see an “explosion” of copepods in your culture vessel. Feed as necessary to keep the water lightly tinted.