HELP ME! No one seems to know what is killing my fish!

[Salty_Hobby]

I will try and answer everyone's Q's here...

They are not snail eggs, I've seen those before and this doesn't look like them.

The white spots are small flat circles, adhering to the surfaces like my glass, thermometer and shelf. Unless I scrub the sides of the tank there is no white junk to siphon off (I don't know if I was clear but it is not free floating in or on the water surface)

Anyone have space to take my Tang? Obviously it would require isolation until we're all sure it's healthy.

I do run a skimmer and a filter (including carbon), my hermit crabs and snails are smaller than nickles so I don't want to give the wrong impression that I have lots of bioMASS, all my fish are relatively small except the tang.

I have been doing water changes twice a week of no more than 25% (as I didn't want to remove beneficial bacteria)

This is where I'm at now: this morning the ammonia levels were still causing my fish stress. I have relocated them for the time being, they should be ok in my reserve tank for now. I will buy more live rock, get a better testing kit and take in a water sample.

As for my Bio load, I think with more live rock the ammonia levels won't be an issue, however, I still don't know what this white junk is or how to get rid of it! So my last option unless anyone has any ideas about irradicating the white stuff... is to entirely clean out my big tank and establish it again (I'm not a big fan of this idea, putting my old live rock back in might reintroduce this white stuff and we're back to square one)

Please let me know if I missed anyones questions!