I do not trust ANY crabs.
Oh goodness i didnt even think about salinity shock.
if you cant get a drip for any reason then you can always do this. temp acclimate for 15 minutes then open the bag and add half a cup of water every 3ish minutes. do this for like 30 minutes tops to prevent ammonia build up. i used to do it that way and it never hurt anything. i use drip acclimating now too though
clowns are not that sensitive to salinity. so i doubt it was rom you dropping them into the tank. i would guess they were not healthy when you got them and from buying them and putting them into your tank stressed them to the point of them dying. did you notice any marks on the clowns or cloudiness of the skin or eyes? seen any signs of other disease in your tank like ich?
i keep my clowns at 18 - 20ppm or i think is around 1.015 or so. i use a digital refrac and only use the ppm cause its easier for me.
are you kidding me!!!! i would be willing to bet the reason they died in such a short time is salinity shock... ALL MARINE animals are sensitive to drastic increases or decreases in salinity..... they can be kept in lower salinity water but they need to be acclimated... not temp acclimated then just dropped in....
Thats not true, there is a lot of marine fish that swim from salt water to fresh water, and sometimes over a very short time. While this is obviously not the same as an instant salinity change it shows somewhat that some fish are very resistant to changes in salinity, even rapid changes.
Pretty much every LFS I have in my area keeps their fish tanks (not coral) at around 1.022 or 1.023, it is cheaper for them to use less salt and is better for higher oxygen levels in the water. If that is the case with the fish in question than even an instant drop in salinity of only .002 should not have been the cause of the fish deaths.
Now none of this is to say his Hydrometer is not significantly off and his actualy salinity is far lower (although he stated he has corals like frogspawn). I would guess his actual salinity is slightly higher than his hydrometer shows.
Again all of this is speculation and something the op should check into. Take your hydrometer into the LFS when you have your water tested and verify its accuracy against their calibrated refractometer.
do you mean from salt to brackish??? big diff between fresh and brackish... and these fish usually go into a brackish area when its high tide and the salinity is at its highest