Agar Diffusion Practical suggestions (collated)

Dabco trays (see below), work well because of the use of the divider.
Dabco Unitray with insert – Haines Educational
Use Dabco trays as a mould for the agar and then just cut it into size.
Use bromothymol blue and vinegar. I can send you the practical sheet and tech notes. Unitrays with the divider removed will give you 3cm Agar if filled to the top.
Just tap the set agar out of the Unitray once set and cut the 3cm3, 2 cm3 and 1cm3 using a scalpel and ruler. Tip – for this recipe, use tap water NOT distilled. 20g agar in 1 litre tap water. 20 squirts bromothymol blue (green-blue colour), heat/ boil and pour into Unitray. Once placed in the vinegar, the colour changes to yellow.
Use different sized silicon ice trays or a Unitray. Use a sharp knife to cut if needed, worked well.
Use fishing line to cut the cubes. Make one large block of agar in a tray / container you have available e.g. a reagent tray that is normally used to store dropper bottles. Turn out the set agar onto a piece of laminated graph paper to measure up whatever size cubes you need.
The Dabco trays, then cut the agar with a scalpel blade.
Use Dabco trays (used for storing dropper bottles) when making the coloured agar.
Fill one completely full, the second half full and the third about a quarter full.
Once set remove the agar with a gentle tap on the bottom.