Is my cider infected

[el_caro]

I put down 2 x 5L glass jars of cider about 2 weeks ago. Both had same ingredients and all seemed same for about a week then one bottle developed a pronounced head/krausen? The other has no head but bubbles through airlock at about the same rate as the one with head.
The head is white and foamy. I tried gently vibrating the bottle and quite a bit of crud sinks to the bottom and the surface in the centre of the bottle clears. It soon reforms a head.
Is this one dodgy and should I chuck it?

 

[Dicky]

Any chance of photos?

Dicky

 

[el_caro]

Any chance of photos?

Dicky

Sorry tried to photograph it but it is in a brown opaque bottle and photos do not show it at all well.

I notice heaps of fine bubbles rising in both jars when I took them out into bright light. One bottle the liquid is quite clear but in the one with head it is quite cloudy white appearance. There is twice the rate of airlock activity in the one with head. Could it be that I incorrectly measured the amount of yeast into each container? It was yeast I had washed from an ale I had bottled a couple of days before?