lowering sg

[ClownieandBilly]

i am going to lower my sg to try and help eradicate white spot.i will be lowering gradually around 0.001 per day from 1.023 to 1.018.i assume the best way to do this is simply siphon out tank water and replace with fresh r/o water of similar temp.

what is the easiest way to raise it gradually when the time comes?

[OrionGirl]

Just use full dose water for water changes, and this will gradually increase the sg.

Keep in mind that lowering the sg to 1.018 won't have much impact on the parasite, but will on any corals and inverts in there. Hyposalinity treatments are usually down around 1.012-1.015. You're better off removing the fish and treating them the full course in a separate tank for 6 weeks. This length of time will allow any spores in the tank to hatch (especially if you boost the temp to 85-87), and die off without a host. Then, with the fish treated, you can safely return them to the main tank.

[ClownieandBilly]

i take it by full dose you mean high sg?
i can not remove fish as there are 6 in my 130 gal and only other tank i have is a 25g which is home to a large maroon clown.
i have been told that lowering sg to around 1.018 will help get rid of the parasite without harming my inverts.
any advice welcome.

[OrionGirl]

The lowered sg will kill some of the parasites, but not all of them, and only during the free swimming stage, which means you have to maintain the low salinity for 4-6 weeks. This is long enough for the lower level to stress inverts considerably, IME.

The treatment tank doesn't have to be a fish tank. You can use any large, clean vessel that will hold water. A large garbage can, or a Rubbermaid tank will work nicely. The point is not to setup a new tank, but to provide someplace where the fish can be treated with ease.