Backyard Aquaponics
A place to discuss aquaponics

I'm anticipating the arrival of my first lot of fish (Jade Perch) next week, so I'm ramping up my system.

It's been recirculating for the past 20 days. I haven't got any plants (except for a few duckweeds) going - my system is inside my shed - because I haven't bought the HPS light yet.

I bought a freshwater test kit from a local pet shop. I think it's the same one you use Steve. The test cards look identical.
I did two tests – one before decanting two buckets of dirty water out of my partner's fish tank – the results were the same for both tests.
- pH – 7.6
- Ammonia – 0.25
- Nitrites – 0.25
- Nitrates – 5-10

I placed a 300 watt heater into the 150 litre tank. I also dosed up the system with some Aqua-Cycle bottled bacteria in the hope that it would kick start the generation of beneficial bacteria in my bio-filter - particularly on the heels of the grubby water that I took out of my wife's tank.

I've got two airstones in the tank - my air pump has four outlets so supplying enough air ought not be a problem.

Anything else I need to do?

You sound very well set up GD, I would expect that you will have very few troubles when your fish arrive, unlike most of my early experiments....

How many Jades are you getting?

About 50 - as part of a shared purchase with Murray.

Thanks for your acknowledgement but I've certainly benefited from reading about the experience of people like yourself, Steve and several others.......and I hope that I can avoid some of the more obvious dramas by taking account of that experience.

GD, 50 is a big load for the bac. to adjust to, but its the same problem that most of us face, we order our fish in bulk becasue teh local shops want to charge $20 for a 15cm silver perch

All i can suggest is feed minimally at the start (will be hard when you see how quickly they demolish the food!) and test ammonia every day until you see it dropping below 0.5

Do not allow ph above what you have it now.

I say these things becasue you are goingt o have a fair ammonia load, feeding less will help this and keeping the PH close to the 7 mark will make the ammonia less toxic while still giving the bacteria a reasonable growth rate. They will re-populate to take up the extra ammonia load. Chnage out water if you see it getting to 1PPM or above (at your PH)

Keep us posted

Steve

Today, I took delivery of my first batch of 50 Jade Perch.

By day’s end, I had lost five of the tiny fish – probably due to stress from the journey from Childers to my place. They had been looking pretty dodgy from the time I placed them in the tank

When night came, I did my water tests…..pH 7.6….Nitrate 5….Nitrite 0.25 and Ammonia 2. The shed temperature was about 24oC and the water temperature was about 20oC. After testing, I dissolved some pH Down in some tank water and put it into the tank in an effort to bring the pH down a bit.

The guy at the aquarium shop told me that tap water around here is probably alkaline which explains the reading. I would otherwise have expected my tank contents to be slightly acidic given that I’ve dosed them with shitty water out of Jan’s aquarium a couple of times.

This morning, I repeated the tests.......pH was back down to 7 Ammonia was at 4.......Nitrate 10 - 15 and Nitrite 0 - 0.25. The ambient temperature in my shed was 10 degrees C and the water temperature was 20 degrees C.

My duckweed seems to be growing again following the introduction of the heater into the fish tank…..and hopefully it will grow even more once it gets a sniff of the rising ammonia levels in the fish tank.

Aren't you worried about the ammonia getting too high? I think I'd have a panic and do some water changes by now.

I would definately have to agree with GotFish?... You need to get those Nitrate and Ammonia levels down.

The ammonia should have decreased when you dropped your pH, not increased. Can you decrease it further? Or temperature?

Definately do at least a 50-60% water change. I know a product called AmmoLock worked for me in aquariums, but I am not sure about chemicals in Aquaponic systems. Get some air into that tank if you haven't done so already and get the return pipe to stir up the water as much as possible.

Woa Woa, back it up a bit!

Firstly I would have left it at 7.6, IMO 7.0 to 7.5 is great for cycling.

However considering your ammonia is THAT HIGH (which it is gary) the 0.5 drop will have lowered its toxicity by a factor of 4, so lucky you did!

Tim: Nitrates are no problem at al, thats what we're aiming for in our aqua systems nitrates of 100+ PPM. Maybe you were thinking of nitrites?

Garry, Water change, now, not tomorrow.

I assume you have not had any fish in there prior to this and have not been supplying any source of amonia to your biofilter? (forgive me if you already answered this earlier)

If this IS the case then you are starting your cycling NOW. Feed MINIMAL and check ammonia daily. Change out water with de-chlorinated and warmed water to maintain =<1 ppm at 7.5 ph (This is the upper limit i would suggest, go lower if it doesn't mean changing out stupid amounts of water.) To bring it down to this from 4ppm you're going to have to do a 75%+ waterchange

Tim, the PH would not have changed the ammonia reading, if anything it may have crept up slightly more due to reduced biofilter efficiency keeping in mind that less toxic does not mean less of.

Print out the chart in this link as a reference point http://www.backyardaquaponics.com/forum ... .php?t=133

while keeping in mind that

So try and maintain 7.5 at 1ppm or less ammonia if you really cant do this then bring it down to 7.0 as it will allow you higher ammonia levels

Oh, and Tim, don't take this the wrong way, but i WOULD NOT drop the temp or ph lower. While either of these will drop the toxicity of the ammonia it will also increase the length of cycling upto 75% (12 weeks instead of 4) so you'll be chasing your tail for 3 months instead of 1.

Better to maintain optimum reproductive and operating temps and ph for your bacteria and keep ammonia down by FREQUENT (daily if needed) water changes. That my opinion.

"Tim: Nitrates are no problem at al, thats what we're aiming for in our aqua systems nitrates of 100+ PPM. Maybe you were thinking of nitrites?"

Yeah I meant Nitrites, mispelling... oops. Don't want to get those mixed up.

"Oh, and Tim, don't take this the wrong way, but i WOULD NOT drop the temp or ph lower. While either of these will drop the toxicity of the ammonia it will also increase the length of cycling upto 75% (12 weeks instead of 4) so you'll be chasing your tail for 3 months instead of 1."

I was assuming that the system was already partly cycled, lowering the temperature and/or pH may increase nitrogen balance time however when it is a matter of survival for fish in toxic concentrations of ammonia it may have to be done for a week or two. Definately agree with the daily water changes though.

Watch the fish's gills you can usually tell in the perch species though a change in colour usually to a red or purple to whether it is ammonia poisoning.

Tonight's measurements.: pH 7....Ammonia 4....Nitrite 1-2...Nitrate 5
......water temperature is 22 degrees C.....ambient temperature is 20 degrees C and Min/Max over the past 24 hours was 10/30.

Steve, I lowered the pH because of an earlier statement you made about lower toxicity for ammonia at lower pH levels. The increase in Nitrites (up from 0 - 0.25 last night) would seem to suggest that the system has begun to cycle.

What's confusing, however, is the drop in Nitrates from 10 - 15 last night to 5 tonight.

I commenced operating this system over three weeks ago......and since then I have added approximately 35 litres of water off the bottom of my wife's aquarium......it was a light brown colour so it had something biological in it. The last 15 litres went in last Saturday.

The fish don't seem distressed but I'll change some water anyway.

I changed about 30% of the water and did some more tests.

The pH remains unchanged at 7.0.....Ammonia is at 1.5......Nitrite is 0.5 and Nitrate is 5......and the fish are all swimming around happily....so far.

I'm trying to get this thing to cycle as quickly as possible so it means hugging the margins......hopefully without killing the fish.

I've got another third of a tank already neutralised so I'll do another Ammonia test tomorrow morning and, if it's still climbing quickly, I'll change more water.

Sounds good garry, the only thing i can think of about the ntrates is the duckweed is using it.

Also agree on the nitrites indicating part cycling. wouldn't have expected this for at least 3 or four days in a "fresh" system.

Keep us posted with your figures

Tim, yeh, its a fine line to tread you know your stuff

I remember whe i was "fresh" i had just measured a ammonia of 4.0ppm at ph of 6.5. I thoguht "no wonder, the bacteria are struggling at that ph" i was about to dose the pH back to 7.5 but couldn't work out how the fish were all still so happy............put the ph buffer down and did further research.........thank god!

Duckweed eat ammonia, if there is no ammonia they convert nitrite to ammonia and eat that. If there is no nitrite they get nitrate, convert it to nitrite, then convert that to ammonia, and eat that...

Point of the story being that so long as there is ammonia present the duckweed wont touch other things it takes too much energy. Duckweed feeding on nitrites and nitrates is highly inefficient duckweed.

Ahh, so for duckweed you want some ammonia?

Certainly prefers it, with none present they'll start on nitrite then nitrate in order of preference. What this means is slower than optimal growth for systems running well, and an ammonia buffer of sorts in a system that has well stocked duckweed.

Adding ammonia to a system is not advised unless you are initially cycling it just adds workload to your nitrifying bacteria.

The duckweed seems to grow fast despite non-optimal conditions, I think if you plan to get peak production it would need to be seperate your system due to the bacteria constantly converting prime ammonia (for duckweed) into second rate food.