Water Changes to reduce Salt in Pond

[blemmy]

Hi Everyone,

Immediately following a PP treatment on my pond almost 4 weeks ago, my filter appeared to have been hit as I had a rise in Nitrite and I added salt to 0.3% to counteract the effect on the fish whilst my filter recovered. Readings this week are indicating that the filter is recovering, (following my adding my preferred filter booster), with Nitrite down to less than 0.1 from a high of between 0.2 and 0.3 on a Kusuri tablet test kit.

I would now like to start water changing out the salt. My pond is unheated and following some issues last year coming out of winter; I would like to get the salinity down and maintain it at 0.15% over winter. I have read an on-line article by Duncan which explains how long it can take to get salinity levels down by water changes and would ask if anyone could please advise me on the following:-

1. Currently I carry out a 10% water change each week - 3.33% every 2 days (due to the K1 in my nexus rising to the top of the central mechanical section every 48 hrs). What is the maximum amount of water I could change every 2 days until the salinity reaches 0.15%, without stressing the fish?
2. Duncan's article on salt mentions that at a level of salinity of less than 0.3 oz/gallon (0.18%), that it would it be safe to administer formalin as part of any possible treatment - have I read that correctly?

Many thanks

Paul

[Duncan]

paul

I did some trail quite a while ago now where I administered formaldehyde at salinity above 0.6% 1oz per gallon and things went great it should be on here someehwere so don't worry to much

did you read my deminished returns article?

that will tell you how long it will take at 105 change outs
dunc

[blemmy]

Hi Dunc,

Yes - in the article I read from yourself on salt, it gave a link at the end to your diminished returns article - absolutely amazing those figures!!

I have had some problems in the past coming out of winter with fish looking a bid red raw on their undersides and thought I would leave the salt in at 0.15% over winter to see if that helps the fish this coming winter. What I wanted was to get the current 0.3% salinity back down to 0.15% (and then keep it there over winter) as quickly as possible without stressing the fish. Could I up my water change (which I do every 2 days at the moment) to 10% (i.e. 30% per week) from the current 3%, without causing the fish stress? Based on your diminished returns article, I estimate if I was doing a 10% water change every 2 days then I would get salinity down to 0.15% in 5 weeks - my question though is would that frequency and volume of water changes stress my fish?

Your advice would be welcome.

Best regards

Paul