Backyard Aquaponics
A place to discuss aquaponics

Hello all.

This is my second summer at aquaponics. Restarted it again in March and decided to go with channel cats. They came from a fishery with red irritation on the underside by their gills where they would lay on they bottom. They had them in a concrete holding tank which I am told had a rough surface to it. I've lost very few fish, but the red spots on the undersides weren't getting any better. So I carried a couple to our fisheries department at the University where I work. They recommended adding salt to the system, along with a little baking soda and epsom salt. I had read about adding salt on your site too. My question is when you talk about 1 or 2 ppt of salt, how do you calculate that for measuring. I read 2g salt / 1 liter. Is that for 1 or 2 ppt?

The system is cycling fine. This morning the nitrites were at 0, NH3 = 0, NO3 = 10-20, PH = 8.7.

But I'd like to add some salt to help spead the healing of these open sores. The fisheries dept. also suggested a separate bucket with a higher concentration of salt, put the fish in there for a short period of time and transfer back to aquaponic system.

For a 100 gallon tank system, would I be correct to calc. 26.6 ounces of salt for a 2 ppt?

Thank you.

G`day Isawthelight & welcome .
That seems to be correct for 2ppt using my leet conversion skills from gallons to litres ,grams to ounces. my head hurts.

I'll second that: your numbers are correct. Channels cats will do fine up to 8ppt and survive until 10ppt, according to some reading I found.

Thank you for your replies. Hoping the salt will sooth their sore bellies.
This is a great web site with so much helpful info. I've been reading the posts for two years, and haven't found it necessary to ask too many questions, since you can search and find most of the answers already given.

However, I do find making a bell siphon hard to work in a shallow (4") container. Is that impractical for such a shallow container. It's the top of the barrel ponics setup and I thought it might be better to have plants get some air occassionally instead of just using a float tray.

I would not salt channel catfish that high. In the reading I have done 5 ppt is the limit for their primary environment so I usually only salt my system to 3 ppt for them. You might be able to do the dip or bath at the higher salt concentration but make sure there is plenty of air in the bath container and don't leave them unattended when doing a high concentration bath or dip. If handling the fish seems to stress them out, you might be better off just salting the system to a safe level and watching to see if it helps. Stressing the fish out may cause more problems than letting the sores heal slowly.

As to the small bell siphon. I put gravel and a bell siphon in the top of my barrel system. I think the inner standpipe for it is about 4" long. I had to go through all the different tricks to get that bell siphon to work. Breather tube, elbows on the bottom etc. At the moment it is a water bed though as I needed to spread out the duck weed. just took the cap off the outer siphon pipe and it keeps the duckweed from flowing down the drain. (gravel/plants were taken out of that top tank when we moved the barrel system.)