Backyard Aquaponics
A place to discuss aquaponics

Hello everybody Andrew M here. We been doing aquaponics now for the last 2-3 yrs, trout s/p mainly. Got 3000ltr tank, (about 100 s/p from 100mm to 300mm not many big ones left) 9x 300ltr grow beds flood and drain with b/metal. Never had a drama with finrot till now? Added new s/p fingers from someone, not my normal supplier- normally we quarantine.YER I KNOW! 2 weeks later finrot. Normaly run tank at 150-200ppt of salt, tried super concertrate of salt 6-700ppt for 24 hrs. Fish came good 4 a few weeks, now itsss baaack must be living in grow beds? Can growbeds be run with high cons of salt for short time, then flushed out with clean water? IF not what can be done to rid this from setup/growbeds, with out killing veggies or us? Will endeavour to send photo's of set up.

Hi andrew welcome to the forum!

Im unsure of your salinity measurements as 150 - 200ppt is absolutely madness and no fish would survive salt levels that high, even if you are talking about 15-20ppt that is still quite high even for a salt bath or hospital tank. For example we usually suggest running a system at maybe 1 or 2ppt which helps mitigate disease and infection and helps provide fish with a protective coating on the skin. I personally run mine at 3ppt and if I salt bath a new batch of fingerlings I salt to around 12ppt for about 1/2 hour every day for the first week. But thats just my routine.

p.s. we love photos

Perhaps he means ppm.... sea water is 32ppt...

How are you measuring your salinity Andrew...

How many fish do you currently have, and what size...

Hi Charlie i put 2 too many zeros in there! it is 3ppt at the moment. have you any ideas on how to get rid of disease from grow beds? will high cons of chlorine/bleach kill our veggies? Sorry again our salt meter is a monach bread and we are so used to saying what in on screen!

Fin rot is a symptom of bad water quality... usually as a result of insufficient filtration... and/or overstocking...

It's possible your beds could be overloaded.. due to high feed levels over time... and perhaps lack of worms???

It's also possible your pH could be way too low... possibly nobbling your bio-filtration....

What's your pH??

How low is too low for pH??

I wouldn't let the pH drift below 6.0 for too long.... the fish might cope... but the nitrifying bacterial colony wouldn't...

Our pH has never gone below 6! at the moment is 6.7. We did all tests again this morning - nitrate non detectable , ammonia is at 0mg/l because of partial water change a few days ago and salt meter reads 267 (2.67ppt). will flooding our GBs with high cons of salt a couple of times and then flushing with chlorine hurt our plants and worms?
Does fin rot stay in GBs ? Which is better bleach or chlorine? We need to eradicate this horrible disease before it destroys what we have accomplished so far!!

Yes... especially the chlorine...

Salinity level of <3 ppt.. wont affect your veges... other than strawberries, cucumbers and snow peas... beans might struggle a bit...

I don't believe that your grow beds are the cause of your problem...

Fish disease is related to stress... and pathogens (always present) strike when stress factors exist...

The two main stress factors with fish... are oxygen levels... and water parameters...

Yea chlourine is a big no-no andrew

What are your GB and FT volumes and what stock levels if fish do you have?

How can we measure oxygen levels?
We have a 90L per MINUTE air pump with 6 air balls and 3 drain pipes from GBs going back into tank!
Our newest addition is the cross bar from pump with jets into tank to circulate water clockwise. When water level fluctuates it also creates bubbles! This has made the water circulate alot more!
How much flow can s/p tolerate?
Can this also be a stress factor?

3oooltr tank , 9 x 300ltr GBs & 100 fish!!!!!!!!!!!

I dont think you have a aeration issue, and flow wouldnt be an issue, you will prob have to keep salt bathing your new batch a few more times. Fin rot wont be in you GB's.

p.s. you can measure O2 with a DO meter but they are expensive.

What's a DO meter? Any other names 4 it & roughly how much?