I have some snail eggs that are different to ones I have seen before.
There are a couple of species of snails in the tank, Turbos, Astria, Trochus, Strombus, Stomatella and nassarius sp.
If anyone can suggest a culprit that would be great, I think that they are nassarius as the adults have been climbing on the glass in that area for the last couple of days in pairs.
The eggs are spread along the glass, approx 1cm above the sand line in the tank. There are 10-15 patches of eggs, with between 20 and 100 per patch at a rough estimate.
The eggs are approx .1-.2mm in diameter.
The first two pictures are of the same group of eggs. The third picture is of another group.