Backyard Aquaponics
A place to discuss aquaponics

Hello from Paw Paw, IL!

I have had my system up and running for about two weeks. I have a 3x3 foot grow bed that is filled with expanded clay. It is about 5 inches deep. Currently, I have 150 three inch rainbow trout in a 110 gallon tank. I truly expect to lose some, so that's why there's 150. It is a continuous flow with half inch plumbing branching above the grow bed to "shower" evenly. I have salad, cuke, tomato, and pepper seedlings in rockwool. So far, I have not lost anyone. I'm currently cycling the system and I've gone through the ammonia spike and now I'm getting the Nit spike.

I've noticed the seedlings are starting slow, and previous threads mention adding worm castings or rock dust to the grow bed. Will this work in a continuous flow system, or harm the fish? Should I just purchase some foliage sprays instead?

Is the grow bed deep enough, or should I consider raising the plants into pots?

Thank you in advance for your input. I left my camera at the office, so I'll post some pics next week.

Well... seeing as "Karl" hasn't graced us with his prescence... we'll just have to call you "goddess".....

Welcome to the forum....

And the "left the camera in the office/car/sisters place"... or the "batteries have run flat" excuse is only good once....

I make 100 gallons to be 420L.... with 150 3" trout... and only a single 3'x3'x5" growbed... you will lose some... maybe even lots... especially as you cycle through your ammonia spike...

Can you post your test readings please...

IMO... you are both groslly overstocked and under filtered... be prepared to do water changes... probably ever second day at least until you can...

(1) get more growbed capacity
(2) get a bigger fish tank
(3) or reduce your fish load

Welcome to the forum

That seems like a lot of fish for that size grow bed, at least as they start growing it will be! Do you have plans to add more beds and fish tanks soon?

Some salt in the system like 1ppt would be good to help you past that nitrite spike, if you don't already have that amount of salt in there. Make sure you have plenty of air going for those fish as well.

Please keep in mind that most of us here use flood and drain media filled grow beds and we generally think of 12 inches as being a good depth for grow beds (you can run shallower but they don't give as much useful bio-filter.) So when I start throwing out numbers, they are generally figuring on 12 inch deep flood and drain grow beds. I'm not entirely sure how well that compares to trickle through beds.
As to how much grow bed you need to support a given amount of fish. We generally figure 100 l of grow bed to 3 kg of fish or 26 gallons of grow bed to 6 lb of fish.

So with your grow bed you could perhaps (if wetting of the media stays really good and even) support just over 6 lb of fish. How big do people usually grow out rainbow trout for eating? You need lots more grow beds to support those fish much longer even if you do loose a third of them.

As to the plants, well we just went through a barren few days for plant growth and now we are entering the root growth stage so I wouldn't expect the plants to be very showy in their growth for a little while anyway, however, some foliar spray of maxi crop (the stuff that is like 0.1-0-1 or something close to that) or even adding a capful of it to the system could help the plants with potassium and trace nutrients. If the plants start having new leaves turning yellowish but the veins stay green, then you need to add iron, chleated iron if you can find it or foliar feed with diluted liquid iron.

Worm castings are nice if you have them, just a small hand full sprinkled over the bed. Even better would be to add a hand full of composting worms into the grow bed to help take care of solid as they build up in there.

I don't know much about rock dust, If I could get some green sand I would use it in my system since it adds potassium and iron.

Right now though, patients and start expanding your system before you crash from too many fish!!!!!!!!!

Welcome Goddess!

Karl must be a lucky man.

Definitely what Rupe said, too many fish especially if it hasn't cycled and especially if they are trout. Are you using a stock tank from Tractor Supply too? I see people mentioning 110 gallons and that pops into my head because I have one of those 110 gallon Tuff Tubs. I also have a 180 gallon Tuff Tub from Tractor Supply that I will be using for trout. I was planning on starting with no more than a couple dozen trout fingerlings in 180 gallon tub, with lots of gravel volume to boot, if that gives you any idea about stocking a new system. I won't buy trout until I have a battery backup installed, as they would all die at the first power outage without one.

eeks! My ammonia is 8ppm with the nitrites at .25ppm. No nitrates yet.

I have an additional 4x4 bed that I can hurry and set up.

Oh... and trout like lots of flowing, highly oxygenated water...

At least you're pumping continuously... but you'll need at least two airstones immediately if you going to hang on to the fish while you organise more filtration and tank volume...

Being trout... I'll actually revise and up my advise to minimum 50% water changes daily...

Unfortunately that will dramatically impact on your cycling...

Do you have enough spare pump capacity to tee-off the pump flow before it enters the growbed... and return some back to the tank??

And don't worry about the plants yet, you need to give it time to cycle first. Worry about adding more beds for biofiltration and keeping the fish for now.

Just saw your last post...

50% water change immediately.... air stones immediately...

And as much as you need that other growbed.... I'd actually use it as another fish tank and split the fish between the two tanks....

Stop feeding immediately.... and don't feed for at least two days... until you get the other things under control...

You'll probably have to do 50% water changes at least daily... possibly twice daily... even if you're not feeding your fish....

You need to get the ammonia down to below 2... and will probably have to salt to combat the nitrite spike....

What is your water temperature???

And a pH reading as well please...

Or find someone to take about 100 of the fish off your hands.

The water temp is about 40 degees (F) and an air pump running full tilt at 400 liters of air per hour through two lines. (Yes, I have a battery back up as well)

I do have a very large pump I can split into another tank.

I pulled one of the fish and ironically, the gills and fins look fantastic.

I'm such a newbie, I'm out the door for supplies!

OK... about 4.5 degrees C.... at least that means the fish will be metabolising slowly... and your water holding maximum oxygenation...

Secondly... your water temp will also be assisting/alleviating your ammonia levels.... not doing you any favours in terms of bacteria growth and cycling though...

Consult the chart attached to get an idea of ammonia tolerances at corresponding pH and water temp values...

With your ammonia reading... I'm picking you've been lucky... and your pH is probably around 7.0-7.5

But you are pushing the limits... act now...

Thats a great table ... Very useful.