Me me! You will want to use f/2 medium mixed up with saltwater, the stuff from Faf would work great here or even the Kent f/2 formulas together, just be sure to dilute them into seawater - 25-28ppt seems to work great for me.
To 1liter of f/2 medium add about 1 small teaspoon of vegan jello (agar, try the supermarket for it). This should yield a nice firm substrate that isnt too loose. Heat the jello mix plus the f/2 into the microwave for 2 minute intervals, stirring inbetween intervals. You're waiting for the agar to have dissolved into the water. If you find at the end its too loose or seem too hard, try again with less or more agar.
Once the agar has dissolved, let it sit out at room temperature, you want it to come down to about body temperature before pouring the plates. Ideally you would do this under a laminar flow hood to prevent contamination of your stocks with bacteria, but so far so good with my attempts at this.
When its lukewarm, begin pouring the mixture into your plates, fill about halfway -
www.aquaculturestore.com stocks petri plates I do believe. When you've finished pouring, start inoculating the cultures with 20-50ml of starter culture of your favorite phyto, a few tablespoons. You wont need a whole lot.
Go quickly at this stage or your agar will harden too much. The phyto can take some heat on their little cell walls without dying so dont try to wait for the agar to cool to room temperature. It will solidify very quickly once its at body temperature, a few minutes working time is all you have.
When all the plates are poured and inoculated, seal the plates with a small peice of tape or two and set them underneath a decent light source that's on a timer. It'll take up to a week before you get a nice vibrant color of phyto growing through the plate itself. Once it gets to a nice thick celled stage, pull the plates, seal entirely with tape (medical tape is my favorite, or you could track down some actual scientific labeling tape) and stick in your fridge.
1 liter of culture plus agar will make up to 40 plates of the 100x15mm size (3" diameter). About 20 of the larger 150x15mm (4.5" usually) size. Scale up or down accordingly.
Plates keep upwards of two months in the fridge, they can be kept under light up to a month before the plate will need to be renewed.
To harvest from plates, pour seawater on top of the plate and allow it to hydrate fully for a few hours or overnight. Take a q-tip and run it across the surface of the gel after its hydrated to bring the cells to the liquid phase of the setup. Pour that liquid into your new culture setup when you want. Dont forget your f/2 in the new culture media.
Any questions?
>Sarah
If you have access to some precise measuring instruments, like a scale, you are shooting for a 0.9-1% solution of agar in your media.
