Backyard Aquaponics
A place to discuss aquaponics

I going to pick up my salt today I know i need a non-iodine salt but how much? I have a 250 gal fish tank with 125 gallons in the sump and then right now I have 4 ibc grow beds so i'm guessing about 425-450 total thinking with the 3/4 gravel will allow for about 50 gallons of water per bed and only having 1 bed about to cycle when I checked them. Any help I would be greatfull.

OK found a salt calculator to figure how much salt I need to add to make my 425 gallon system 1 PPT it said 35.89479 lbs :0 is it really that much? here is the link I used
http://www.csgnetwork.com/poolsalinitycalc.html

Salt works in too ways.

1 boosts the slime coat on the fish which is helps their immune system.
2 the sudden addition of salt to a system causes parasites to explode. The cells walls of the parasites can not osmoregulate (deal with the salt) very quickly and if you increase the salt concentration quickly they cant cope. Which is why you want to increase the salt concentration in a jump of 3ppt and you want to do it quickly. If you already have say 2ppt of salt you want to add 3 to bring it to 5ppt.

Here's what I generally recommend as far as salting.

Salting
Nitrite issues - 1ppt = 1KG per 1000L or 1gm per L
Parasites - 3-6ppt
Dip for parasites - 30ppt - .5 to 10 minutes. Remove fish showing signs of distress immediately (laying on side or erratic behavior for example). If you do this be very careful some fish will not do well and could die with this level of salt.

Lets see then - We know there are roughly 2.2Lbs per Kg and roughly 3.8 liters per gallon. We also know that 1ppt = 1KG per 1000L

425 gallons is 1608.8 Liters so it would take 1.6088Kg to make a 1 ppt solution which is 3.5468 lbs of salt.

My calculations are just using online calculators and pretty sloppy as well but just looking at the line above tells me something is not right with the result you got. I haven't actually looked at the calculator you used yet but just thought I'd let you know - looks off by a factor of ten .

This is why you guys should go metric. So much easier.

That would be great but not happening anytime soon Stuart

thanks, if this calculator is off then that would explain why my plants look like they are dying.i'm going to start adding fresh water back to the system today and hope they can recover.but if not at least the fish i have left seem alot happier. afetr checking the calculator it seem that human error has struck again I was reading it wrong but it wont happen again. I'll get some pics up soon. thanks all

ok so for the record Channel catfish will take up to 10 ppt salting and do just fine.... on the other hand squash cucumbers bean and peas wont my next question do I need to do water change outs to lower the salt content or will it lessen over time. the last rain we got I collected about 300 gal rain water so I though about changing it out. what do you all think?

catfish can tollerate levels up to 16ppt and motalities occur between 16ppt - 22ppt. Although, it should be noted that they start slowing and go off the feed at 8ppt and 10ppt respectively.

that is interesting thanks for the tip on the salt. I know the people I got the catfish from said they did not believe that the fish would live in tanks and all I was doing is throwing money away.