Hypo salinity can work, if it is ICH. The cysts will burst if done properly, however, the ICH is in the main tank and if you, lets say, kill the ICH on the fish and put them back in, they will most likely get it again so, it is best to leave them quarantined for 4 to 6 weeks. The 29 gal
, you can leave the sand in, or take it out..
I would hold off on using copper right now unless it is real bad... If you can get RO
water, I would go for the FW
I would keep the 29 at full salinity, and then get a good size bowl, fill it with 80% RO
water and 20% tank water. The PH
should be raised to the same of the main tank, by adding sodium bicarbonate (usually 1 tsp per gallon). Get it to the same temp as the tank, and then slowly lower the fish in and watch carefully. DO NOT LEAVE IT ALONE. Leave the fish n for no more than 10 minutes. Some fish will only allow this for 3 to 5 min, before show signs of stress.. This should be enough, and then slowly lower the fish back in the 29 gal
.. Continue to watch the fish for signs of the disease decreasing.. After it is gone in about 10 days, do not get anxious and put the fish back in the main tank.. Let them stay in the 29 for about 4 to weeks... Thsi should get rid of it...
Again, I would hold off on any copper products unless it is entirely neccessary....