How important is the 48 hour rule for lowering salinity?

[old_salt]

Is there a problem with taking longer than 48 hours to reach hyposalinity? I started hypo on Friday night (removed 2 gallons and replaced with 2 gallons of fresh RO water) on a 55 gallon tank. Replaced another 2 gallons before leaving for work on Saturday morning at 4:30 am and came home from work to find one of my 2 bannerfish had died (other than having a few spots he was eating and acting like everything was great until I started hypo). Anyhow I have now backed off to changing the water 1 gallon at a time every 4 hours and it is going to take at least another 48 hours to get the salinity down to 1.009 in this tank. Will this reduce the shock factor to these parasites or will it just take a little longer to kill them? I have 9 other small fish in this tank and don't want to end up killing them all off before I even get the salinity lowered to hyposalinity. Thanks for your input!

 

[flcandy]

What parasites are you treating for? Also there is a problem with lowering it to slow as they can become accostomed to the lask of salt in the water.
Need to know what your treating for though...

 

[old_salt]

I was restocking a 46 gallon tank that had been sitting fishless for over 2 months with fish that were coming out of hypo. Two weeks after fish were added the 2 bannerfish and the copper banded butterfly showed signs of ick. I transferred them over to a 55 gallon tank I had set up for QT (had a few pieces of live rock in this tank but have since removed them). I keep this tank running just in case something like this happens. Water quality is good, but have added some Prime just in case of an ammonia spike while dropping the salinity (I added this after the bannerfish died). I just hate to stress these fish out by dropping the salinity so fast. I am now at 1.015 and should be down to 1.012 by this time tomorrow night.

 

[sepulatian]

You allow the ich to adjust to the lower salinity if you do it slower. 48 hrs is enough time for the fish to acclimate. You don't want ich to acclimate. It is said that after the SG reaches 1.009 all will be fine. We have had members report that the ich was living way past a week in hypo when they dropped it too slowly. Some reported two or more weeks after reaching 1.009 when they dropped slowly.