While checking on the plant in the bucket earlier, I realised it was looking a little rough. I lifted the lid of the bucket and the roots are growing nicely, but there was a white frothy substance on the surface of the nute solution.
I think the nute temps are too high, as I have not done anything different from my last grow which never developed froth. The only difference is a warmer grow area.
So I have changed the solution and will see how it goes.
If anyone has a suggestion as to what could be causing the froth, please let me know.
Thanks all!