Backyard Aquaponics
A place to discuss aquaponics

You've got an uncycled system... around 14 days old... with 40 remaining fish... in a 500L tank.... about three times more than you should have... was more like 4 times...

You were feeding them... and the ammonia is through the roof... at a water temp and pH that puts you on the edge of fatal ammonia toxicity...

I'm unsure if your bio-filter is even sufficient capacity... even if it were cycled... but it's not...

Personally... I would remove 50% of the fish into another tank.... do another 50% water change... NOT FEED ANYTHING...

Wait, and pray, that it's not too late to save about half of them...

The filter is 50L with aproximately 30L of hydroton in it. Is this enough ?
I acknowledge the error in not cycling the filter first and I am now paying the price or should I say my fish are paying the price.
Apart from the couple of small feeds they got in the first couple of days there has been no feed now for 10 days. The second tank sugestion is not an option for me so I will go with another water change and keep the fingers crossed I havent pushed them too far already.

Hummm... if you can't split the numbers... then another water change will bring the ammonia down (for a while)... but will also alter the pH... and probably the water temp...

And you're on a knife edge... with stressed fish anyway... and it will slow the cycling process a little...

You could reduce your ammonia toxicity... by lowering your water temp slightly... although with that might add more stress to your fish...

Ok.... what I'd suggest is this.... at this stage... don't do any water change.... reduce your tank temp to about 22 degrees... this will nearly halve your ammonia toxicity....

Then do a 10% water change... retest and post the results please... including temp...

P.S ... did you resalt after doing the last 50% water change??

Well if you have up your aeration and the ammonia is still not coming down, then it would somewhat suggest that your 30L hydroton is insufficient filtration.

I have just got an idea... What temperature is your sump tank of your other system at the moment? With the weather warming up in Perth at the moment, almost too warm for the trout, it could be at the lower limit of what the Barra can take... What is the lowest temperature Barra can take?? Anyone? Rupe??

If it is possible, then move half the barra into your sump tank...

Ivan,
The temp in my sump tank is around 20 deg so I would say this would be the absolute lower limit. Even with the high temps experienced on Saturday my water temp only reached 22 as all of my tanks and GB's are under shade. This is the avenue I will take though as the temp begins to rise.

Rupe
When I did the previous water changes I salted and heated the water to match the FT prior to the change. I will get the better half to drop the temp on the thermostat and do the 10% water change for me during the day and I will post the Test results tonight when I get home from my day job.

Update for last nights water Tests

Temp 25 and falling
PH 6.6
Ammo 4
Rites 1 - 5 ???
Rates 10

Death toll 18 from 58

How are they doing?? Has the ammonia come down yet??

Hi Ivan
No luck yet with the system. The ammo is still regularly around 4. I have carried out additional water changes, reduced the temp, added another filter and starved the fish for the past two weeks and still it wont drop.
I am not sure what my next move will be. I have lost a total of 21 out of the 58.

MDB,

Go to any aquarium store and purchase a product called "stability" (I think it's made by seachem). This stuff contains the bacteria needed to colonize and produce a biofilter to convert the ammonia to nitrates. Follow the instructions (add the right amount each day for a week) and you should provide enough bacteria to reduce the levels of ammonia significantly. While you're there, talk to the fish shop ppl and tell them the volume of your tank and the number and size of the fish you have in there. They may be able to suggest alternative products that are even more effective, however I have used stability many times and it has enabled me to heavily stock my home aquariums without waiting for the filter to cycle. Oh, it shouldn't have any toxic effects on your plants either.

Hope it all works out ok for you

Good luck!

Antisense ^_^

The next move should be to do as little as possible?

I learned the hard way (but certainly not as devastatingly hard as your learning process so far) that human intervention in this process, especially early on in the colonising of the bacteria can be disastrous. Although we generally think we only farm two "flavours" of bacteria, they have their preferences for growing so think of each flavour as having many "sub-flavour". Each sub-flavour grows when it is acclimatised to its current environment in terms of pH, temperature etc. If everything in the system is constantly changing, the bacteria cannot colonise; for example, if the acid-loving flavour of bacteria get a start and then the pH goes up, these bacteria will die and the base-loving flavour will begin to establish themselves, if the pH goes back down again, then these will be dead too and your back to the very start with absolutely no bacteria to process the wastes in the system. The same thing happens when there are wild fluctuations in temperature, salinity, alkalinity etc. Even in established systems, sudden changes in one factor can initiate bacterial death which sets off a chain reaction of events which usually leads to massive system failures and catastrophic losses. I like to think the AP principle is to farm the bacteria, with fish and plants by-products of this activity. If you cannot keep the bacteria alive, there is no way to keep the fish and plants alive.

Adding more filtration is not going to do much for the system, except for removing particulate matter. To drop the ammonia levels from the critical levels where they are now requires bio-filtration. Bio-filtration needs bacteria. Bacteria need stable conditions and time. To lessen the establishment time, try to find another local AP aficionado who has similar water conditions as yours (or as close to yours as you can find) and obtain some of their pond-gunk or used filter material. These will contain some bacteria which wont die of shock as you introduce your water to them, and should happily establish themselves in your system. You could also try adding a small quantity (couple of handfuls?) of worm castings to your growbed as the micro-organisms etc in this (allegedly) promotes beneficial bacterial growth. There are some commercial products available from aquarium shops which are also supposed to promote beneficial bacteria, but the reports I have read/heard give mixed results (but when there are no options left, it might be worth a try?)

With the aim to stabilise as many factors as possible and let the good bacteria get established with as little intervention as possible, I think the best thing you could do for the system is to keep it as cool as practicable and is sustainable (to reduce the TAN toxicity), keep up the increased aeration and pumping, and small but frequent water changes with de-chlorinated water which should not affect the pH or temperature. No feeding the fish! Wait. Wait. As hard as it is to do, wait. Cycling a system can take months, although it can also be achieved in just a few weeks given the right conditions; I doubt it is possible to achieve a cycled system in just a few days? This is going to take some more time, pretend you are starting from scratch and work on that premise.

You might also like to try cycling some of the water through a second pond containing duckweed, watercress or other aquatic plants that can directly take up ammonia from the water; DO NOT add it to the fish tank as hungry fish will eat it and then you will be in a whole new world of hurt as they digest the feed and excrete more waste! (I am not sure if barra are STRICT carnivores? It's not worth the risk?)



Scott

P.S. You still have my number if you want to chat?

MDP... please give us a complete breakdown of your system configuration...

I know you started with a 500L tank... and a "filter" that contained 30L of hydroton...

And have since added another "filter" .... what capacity and style of filter is it??

I'm picking that both "filters" are probably the same size... and being run as "trickle" towers???

How is the water pumped through these filters.... continuously??


IMO... The reality is simple....

You still have 37 fish in a 500L tank... with probably a max of 100L of filtration...

That's twice (+) the number of fish for the size of the tank... (how big are the fish please)

With... at best... 1/5 of the necessary filtration capacity required...

In an uncycled, imbalanced system...

Your filtration capacity just isn't capable of dealing with the daily ammonia production of your fish... let alone any feed.. which thankfully you're not...

The continued high ammonia, and (to a lesser extent) your pH ... is inhibiting the conversion of nitrites to nitrates... it wont happen until the ammonia is processed...

You are probably maintaining an artificial level of nitrites if you are running a trickle tower, with continous flow... and again inhibiting the nitrification...

Your system is in a constant state of imbalance.. and under filtration...

Sorry Bunson... but I totally disagree with you... adding more filtration .. is the only way that you will be able to alter the situation...

Adding additional filtration will provide additional surface area for the bacteria to expand and colonise in order to provide the level of bio-filtration...

IMO... you need to add at least 500L of filtration capacity... preferablly in a flood & drain configuration...

IMO... if you do so... you will see the ammonia... and the nitrites fall rapidly... and you may save your fish...

Don't do it... and IMO... no matter how much/many aquarium products or chemical treatments you add... you will not alter the situation...

And your remaining fish will die... either from the effects of prolonged exposure to ammonia and nitrites... or from opportunistic pathogen attack due to poor health and stress in your fish... or from starvation...

Hi all
I appreciate the advice as I obviously need as much as I can get.

Rupe
I can understand how I am light on for filtration but a 1 : 1 ration of filtration to water volume for 35 + fingerlings seems excessive. I have read so many posts that talk about a 1000L FT with a 500L GB suporting 20 - 25 full grown trout so I am struggling to to understand how the fingerlings I have that amount to around 1Kg in total body mass can produce so much Ammonia.
I read the Barra Experiment posts from VeggieBoy where he maintained 100+ fingerlings in two 180L tubs that were filtered by a 25L home brew tub so this led me to believe my filtration would be sufficient.

The system now comprises of a 500L ft with a 2000L p/hr pump which pumps up through a Aquapro 5000 pressure filter which in turn discharges into my home made filter via a 25mm line that has a venturi in it to oxygenate the water as it enters. This filter is a 50L bucket that is styled on the designs posted by Bentaz. ie : water enters from the top via a center pipe which pumps the water to the bottom then it raises up through the hydroton and then passes through 40mm thick filter foam prior to discharging into the FT. The whole system runs 24/7 so I guess it is what you would call a trickle tower.

The water readings are as follows
Temp - 22
PH - 6
Ammo - 4
Rites - 0
Rates - 20

I am monitoring the temps in my main system and they are sitting around 19 - 21 so if they continue to hold here I am considering taking half of the fish and putting them in my sump. There is a risk with a possible cold spell but the current arrangement is a risk as well.

MDP,

Although the study (below) was conducted on bass, from my readings so far it seems to hold true for a much wider variety of fish species, maybe even all fish species?



In short: Smaller fish have higher metabolic rates than larger fish and as such they create more waste.

Whilst trying to learn about a fish species I had never heard of before AP, the tilapia, I came across this book which explains a lot about a lot of things, including ammonia, nitrification ,bio-filtration and more. There are heaps of research papers and books out there, but I have kept this one because I often find it helpful in a variety of situations:

Tilapia Culture, Abdel-Fattah M. El-Sayed, 2006
See: http://www.docstoc.com/docs/10876030/Tilapia-Culture

Although not written specifically for aquaponics (although AP gets quite a few mentions throughout the book ) I recommend this book as it explains a lot about what is going in general fish-husbandry, water quality monitoring and the nitrogen cycle etc. It gets a little scientific in places, but everything comes with pretty good explanations in (relatively) non-scientific terms. Someone hosting tilapia would find this book useful, but I think everyone in AP would get something out of book too; even if it is only the awesome reference list at the back of the book so you know where to start looking for other specific information.

If there is some good news; in the report Acute and Postexposure Effects of Ammonia Toxicity on Juvenile Barramundi (Lates calcarifer [Bloch]), Asle Økelsrud and Richard G. Pearson, their research shows the long term growth of survivors of high ammonia exposure as juveniles is not significantly affected. (The keyword here being, survivors.)


Scott

Thanks for that Scott.
Yes I do believe the key word is survivors and hopefully I will have some.

Ok, I'm just home... and I'll be busy most of the weekend... but I promise to dig up the relevant figures/formulas....

And reply more fully later...




No a 1:1 ratio of filtration volume to water volume is not excessive... it's the absolute minimum

In fact... it was always suggested, repeatedly... that ALL systems should be designed with a 2:1 ratio.... in order to meet the necessary fitration requirement of fish bio-mass at point of harvest...

REPEATEDLY... suggested...

Lately... it has be REPEATEDLY IGNORED.... and a 1:1 ratio has become the norm... as have FISH DEATHS!!!

To the point that I've bit my tongue many times and not posted... because frankly (no offence personally)... I'm getting the shits with people killing their fish...

The 1:1 ratio acceptance seems to have been based on the observed behaviour and stocking densities of Tilapia... a fish which is tolerable of incredible bad water quality parameters... and often pictured within intensive aquaculture operations... at ridiculous densities...

But not shown.... is the heavy duty solids removal filters, direct oxygen injection systems... massive bio-filtration systems... and constant water changes... that support such operations...

This attitude has become compounded by the release of many dinki-di systems from "band-wagon jumpers" and "box movers" into the aquaponics market...

Sadly, there's always never feedback posted by anyone that actually buys these systems... but I'd bet my house on the reason being... they become abandoned... after they kill ALL the fish...

Please link to those systems that you say support 25-30 grown trout... in 1000L tank and 500L of filtration.... as I'd like to review them... and ascertain what size they were when harvested... and how many were lost along the way...

And whether they were "mature" systems... or newly cycled systems...

I’m picking most fish were probably harvested around the 500-600gm mark (max)…

An equivalent stocking rate of 15kg/1000L…. half the “suggested” density… with about half the suggested minimum filtration…



If you reveiw VB's system thread... you'll find that yes... he initially stocked about 100+.... <20mm... in about 300L of tank volume... with a pre-cycled 25L filter...

For about 3 days before removing the remaining fish.... 45 lost in 3 days... into a 50L aquarium with 2 filters... (presumably 2 x 25L)... then into 2 x 50L aquariums each with a filter...

And continued to suffer losses... before moving the bigger fish – unknown number… into the two 180L tubs that were filtered by a 25L home brew tub… that you mention…

Before moving them again, about a month later into a 1000L tank with growbeds attached…

Because of “the amount of crap they’re creating”… and because ” 50% water changes every week have become necessary to keep things from going pear shaped” … as well as… back-flushing the filter…




Couldn’t find a lot of info on the Aquapro 5000… seems to have been discontinued…

But what I did find suggests that it was sold as a “pond” filter …



For $139…. A bloody cheap filter for it’s supposed rating…

But yes… it would appear capable of filtering your tank, in conjunction with you other “upwelling” filter…. when cycled

But you’re not cycled… and until your ammonia disappears… you wont convert nitrites to nitrates… and with a “continuous flow” filter system…

IMO… this could take some time…

Seriously… if you were to get two blue barrels… cut them in half lengthways… to make 4 growbeds… still pumped continuosly… but flood & drained by loop siphons…

I’d put my money on you cycling within a week…