Rate Of Decreasing Salinity Of A Freshwater Tank

[NeonBlueLeon]

Heya folks,
 
I just finished treating Ich with salt and heat, and I am beginning to prepare to desalinize the water back to normal.  I had added 12 tablespoons to 20 gallons of water (3 tablespoons per 5 gallons) over the course of 36 hours.
 
My question is, do I need to decrease the salinity of the water slowly just as I did when increasing it?  I was given advice to do a couple 50% water changes to decrease the salinity.  Is that too rapid of a change for the fishies?
 
Thanks for any help!

 

[Lunar Jetman]

Well you added it over a relatively short space of time so I don't think it's that big a deal. I'd carry out 20% water changes daily for a week or so unless anyone else has any view on this?

 

[eaglesaquarium]

I think that's a fairly good plan L.J.  - I'd suggest that when refilling with each change, to do it slowly... let the water trickle in if possible over the course of an hour or so.  That's slow enough, even the most sensitive fish in your tank should be fine with it, but fast enough that it won't tie you up forever.
 
 
I use a hose connected to my kitchen sink, so a slow trickle is easy to achieve for me.  Not so for everyone.  If not, I'd still spread out the refill over the course of at least a half-hour up to an hour.

 

[NeonBlueLeon]

For all my PWCs, I actually use an air hose.  I have a bucket of tank-ready water that I raise above the tank level, place one end of the hose in the bucket, suck the other end like a straw, and place the other end of the hose in the tank.  Gravity will do the rest of the work for me.  I usually feel like the flow rate through a standard air hose is slow enough, especially for larger tanks.
 
If there's a large temperature or salinity difference, I put a valve on one end to control the flow.

 

[eaglesaquarium]

That should work perfectly - plenty slow.  The concern I had was someone just dumping water into the tank as quickly as they can from a bucket.