Backyard Aquaponics
A place to discuss aquaponics

Hi all
We are still having troubles with finrot? Does high hardness increase stress? We have isolated fish in quarantine tank with salt levels 5 ppt, they come good then when returned to 3000ltr tank, they get sick again! 3000ltr tank has just under 100 fish now! Not all get finrot but it's still a problem in our system? Here are the test results we have done this morning.

GH 180 ppm
KH 0 ppm
pH 6.5
NO2 0 ppm
NO3 40 ppm
Amonia 0
Salt 3.5 ppt
water temp 20 oC
DO is great

Does anyone have any more information that may help us please?
Major Concerns
Andrew

Your general hardness isn't a problem... you carbonate hardness could be... and your pH will probably drop rapidly....

Keep an eye on your pH... if it falls to 6.2... then "kill two birds with one stone"...

And buffer the pH back up with a Calcium buffer... like "slaked lime" (Calcium Hydroxide).... or some Calcium Carbonate....

You could, and it's probably opportune to do so now... add some shell grit.. either to the grow beds, or in a sock under a water return....

This will self-regulate the pH... and add to your carbonate buffer (hardness).... as well as providing a source of Calcium for your plants... and the nitrifying bacteria...

Your finrot is no doubt related to water quality problems, or more likely ... over-stocking...

How many grow beds, and/or other filtration do you have on your 3000L system???

We have 9 x 350ltr grow beds flood and drain off 3000ltr with just under 100 SP now ranging size from 100mm to 250mm, so we don't think that over-stocking is the problem, we have had more fish with no probs previously!

You're certainly within acceptable limits....

But fin rot, disease... is always related to stress factors... and water quality is usually foremost...

Your aeration seems OK, as do you water tests.... and pH isn't that low that it might be causing problems...

What test kit are you using to measure pH???

And what's the general appearance of your water??

Here is a link the the system viewtopic.php?f=18&t=11505

We are using 2 pH test kits - AQUA MASTER Bromothymol Blue pH Indicator Solution and API Aquarium Pharmaceuticals 5 in 1 Aquarium Test Strips ( Fresh and Saltwater Aquariums)
The water is slightly amber in colour but crystal clear.

Humm... so the pH reading is probably true... and the description of your water sounds OK...

Looking at your photos of the fish... while there's a slight degree of fin rot.... there seems to be a more wide spread "blotching", with possible scales missing...

Leads me to suspect either a bacterial problem... or a reaction to some sort of leaching, possibly mettalic.... (any chance???)

I think you're going to have to bite the bullet, and chance the plants.... and salt the main tank to 6ppt... and leave for 1-2 weeks...

Yeek... looks like a similar problem that "mattaquaponics" is having.... Aeromonas salmonicida... but milder...

Although it's not known to generally occur in WA... (Troutman - can you confirm existance over there.. and/or treatment??)

http://www.daff.gov.au/animal-plant-hea ... al_strains

Note the part that says...



I'll see if a salt dip/bath can be effective...

That one fish which is no longer was in quarantine tank and was for 2 weeks with salt at 7ppt now at 5ppt and was 1 of 4 fish that looks like that? These fish will NOT be going back into main tank!

All the silvers in 3000ltr tank do not look like that but some do have minor fin rot? We have tried 7ppt in main tank with 1000ltrs of water for 24 hrs and isolated GBs and they seemed to go well for a couple of weeks but problem keeps coming back?

Mettalic couldn't be a problem unless it's in our drinking water is contaminated? Our set up is plastic, pvc and fibreglass! The only metal is 2 small pieces of galvanised wire holding cross flow pipe up? Which has just been removed now. Time will tell on that one?

Can we use lime stone as well as shell grit in our grow beds? Shell grit has also been added now today!

Mattaquaponics case is severe... and your symptoms aren't a complete match...

But here's my response to Matt... please note the caveat(s)...

viewtopic.php?p=316653#p316653

Hi All
" Slacked Lime " (Calcium Hydroxide).... or some Calcium Carbonate....
We have searched our local area and surrounding areas for these products, even the hydroponics store?
Still no luck at this stage! Does anyone know where it might be sold here in South West WA?
Is normal lime stone the same? If so will it be enough?

Cheers for any info that may help us.
Andrew

Try a building hardware supply Andrew.... also known as "hydrated" lime.... or "brickies" lime...

Thanx Rupert. Thought that was the same stuff? why didn't you just say that in the first place?
Technical names are sometimes too much info for some people! HaHaHa
Is normal lime stone the same? If so will it be enough?

Yes and No... limestone... or just lime... is Calcium Carbonate....

It will buffer/raise pH.... but not as quickly... and/or you'll have to add more of it... (in small doses)... (shells, shell grit... is Calcium Carbonate)

All "carbonates, bicarbonates" will raise pH... as will all "hydroxides"....

Strenght (lowest to highest)..... Carbonate>BiCarbonate>Hydroxide ....

P.S ... "Dolomite" lime.... is a mixture of Calcium, Magnesium Carbonate....

I thought dolomite lime was bad for AP rupe?

---or maybe it was another lime, cant remember now