Am I infected?

First time making cider. I pressed about thirty gallons of cider with the help of friends and froze it before I decided to try to make hard cider. I thawed 4 gallons , and placed the cider into 4, 1 gallon sanitized jugs. I added 1/2 cup brown sugar to 2 of the jugs and a campden tablet to each of the jugs. After 24 hours I added approx. 1/4 of a packet of D47 yeast. The primary fermentation took off well with OG of 1.055 to 1.065. I racked to other gallon jugs after 7-10 days with a gravity of 1.002-1.004. I attempted to make up the volume lost with marbles, boiled, cooled and sanitized. There still was some space on the top of the jugs but it was better than nothing. After about two weeks in secondary I'm noticing what looks like dust on the surface of the cider in a couple of the jugs. The air locks were filled with vodka and though there is no bubbles coming from them there is pressure there shown by a difference in liquid levels in the air locks. Is the " dust" I'm seeing a problem? I used starsan for sanitizing everything touched by the cider

 

A picture really would help

 

View attachment IMG_1509496911.744111.jpg

 

This is the best pic I could get using an LED light stick to show the specks. This jug has the most marbles in it and more of the issue than the others. The marbles were still wet with starsan when they were put in the bottle.

 

Did you get to the bottom of this? Is there a chance this is something physically coming off the marbles you put in it, or some sort of a reflection they are giving off - the second one is a long shot and a complete guess as I have never heard of someone putting marbles in their brew.

A simple way to see if it’s infected is to pull a sample , if it smells odd or tastes like vinegar you have your answer.

The only time I saw something that was infected was when I used blackberrys to make wine and someone lifted the lid at some stage and something must have got in, that ended up being covered in white specs and was obviously infected.

Either way once you get to the bottom of this I’d be interested knowing what this turned out to be.

 

I was told to put marbles in the brew to raise the level in the bottle during secondary. The specks are still there and haven't changed any. I expect another week or so til it clears more till I get a taste. I cleaned the marbles well by boiling them and soaking them in sanitizer but they are where the specs are.