Could It Be ICH ?

Hiya.
My 2 Clowns and humbug damsel seem to be rubbing themselves off a certain rock. They only do it now and again and they have been doing it for quite awhile now. Except, Its only on one spot on one rock, they do it no where else but that one spot on that one rock :-/
Could it be ICH ? I havnt noticed any white spots on them at all, Why are they only rubbing off the one spot on the one rock and no where else
?

Thanks
Conor

 

If it's just the one spot on one rock I'd say probably not but I'm no expert so answering a few questions may help others help you better...
What are your current water parameters?
Are they eating/behaving normal?
Do any of the 3 show signs of labored breathing?

This link my help you as well
How to Identify & Prevent Saltwater Ich (Cryptocaryon irritans)

 

Do they spaz out against substrate, or just spazz, is breathing labored, if so yes

 

Done some testing today

Ammonia 0
Nitrite 0
Nitrate 20
pH 8.2 (added a tiny bit of buffer)

 

What do you mean by spazz out against substrate
Breathing is fine.

 

UH OH! Just checked the salinity and its 1.028
D:

 

How much water should i take out to replace with fresh water ?

 

Ok I took 3g of water out and replace it with 3g of warm RO water. The salinity seems to have gone down now to 1.023
Pewwwww

 

Like they will be swimming fine, and then they will dart towards rock quickly, turn sideways, and hit it and just swim on its way

 

Yeah, i think iv seen them do that