Backyard Aquaponics
A place to discuss aquaponics

Live about 250km north west of Port Lincoln, SA. Have bought Joels book & read , several times & looked for the bits I missed, cant find it.
Completed setup with 1000L tank & 2 polysheeting with liners grow beds(2000L in total) with limestone gravel, washed somewhat.
Have in excess of 60 yabbies, doing very well. Plants appear to look ok for a few weeks and then fade out, in the most agonising death. Have been watering 2nd daily with seasol & putting a glog(an exact measure) into the draning system.
Initially put a 210ml bottle of nitrobact used in fish tanks with the 2 types of nitrite & nitrate blokes, as directed by the PtLincoln pet shop. Tried to buy the little chaps from Joel but couldnt buy seperately.
Water test is 180GH, 180 KH, PH 6.5, Nitrate 20 & nitrites 0.5. Can you help me as Id hate to die like these poor unfortunate plants.
I have talked encouragingly and did wisper a small spot of abuse but neither appeared to make any difference. Help from Dreamer

hmm it seems a little odd that your ph is as low as 6.5 using limestone gravel.
if you hadn't said you'd tested i'd swear it sounds like your ph is through the roof and the plants aren't able to absorb the nutrients.

we might need some more details to solve this mystery
1. what plants exactly have you had in the system
2. what kind of position are they in? how much sun are they getting? pictures might help

i'm going to concur with timmy

your GH and KH are the same so i'm going to assume that the magority of the hardness is calcium carbonate.

yabbies are happiest at about ph 8ish and i'd expect them to be trying to escape at 6.5...........plant pics would help heaps, but i bet they are yellow as?

re-check your PH using another test. are you using the drops or pool strips? strips are next to useless.

I'm guessing that you're somewhere near Streaky Bay?

Suspect that the pH is probably down around 8.0 with the "limestone" gravel.... so not surprising your yabbies are doing well....

But if you look at the nutrient chart .... at pH 8.0 you'll be locking out the iron and most of the other trace elements as well. Even your phosphorus uptaketo a certain extent.....



Probably a classic iron deficiency as Steve suggests.... sounds like you need to get some chelated iron or maybe even better some "MinPlus" rockdust into the system....

Pics would help and I'd agree with Steve and Timmy that you need to re-check/re-test your pH

Yeah, king Erik, near Streaky Bay.
I have just thought, due to evaporation I added water yeaterday a couple of hours prior to the test. Will go and retest this am. Feeling a bit computer challenged today, cannot import my photos. Will keep trying. The plants actually go an agonising purple, brown as well as yellow, just a miriad of colours. What additives can you add? Chelates? & what? Dreamer

Several tests later, todays test tells me gh 180, kh 120, ph 7.5, no2 1,
no3 is about 30. My test kit is an aquarium 5 in 1 kit, due to distance I dont have access to professional testing, is this kit okish?

The iron chelates & seasol mix every couple of days gave it a less agonised look. This week a algal scum has formed on the outside of my tank, is this ok?

Is there a prescribed population of yabbies to a 1000L tank?

Is there an area to refer to as a guide to trace elements that dont tend to kill the yabbies / fish, and any other additives?

The 5 in 1 Master Test Kits are what most of use Dreamer.

Good to here the chelated iron and seasol have perked your plants up a bit......

Your "nitrite" reading and sudden appearance of algae might suggest you're still cycling.... if you've been running for a while in might just be a bloom from exposure to the sun....

Perhaps both your tank and plants might benefit from a bit of shading.

If the algael build up is just around the sides of the tank I wouldn't worry about it..... watch those nitrites though...... not sure how yabbies respond to pH & nitrites.... will let others comment.

If your test kit uses drops and test tubes, it's great. If it is a strip with pads that change color, it's not as great, but better than nothing. You can mail-order decent test kits for minimal price and they brings it right to da door. Amazing.

We don't have guidelines for iron/seasol (I don't think), but if the plants look nice and the fish are still hungry, you're fine. I did go overboard with kelp tea at one point, and the fish let me know things were amiss. They all sulked on the bottom instead of coming to breakfast. I supplement with a splash of chelated iron and a spoonful of phosphate every couple weeks--or whenever I remember. The leaves of the peace lily tell me when I need to pay attention to that.

Since we gauge everything by volume and critter-weight, I would think yabbies could be handled the same way. In English, it's 4 gallons growbed to 2 gallons tank to 1 pound critter. One of the metric folks will have to give you ratios--I barely get the english ratios right. One of these days I will memorize the metrics.

Hi Tommy Dreamer,

is ur 1000lt tank an ibc? If u have access to some shadecloth, cut it into 20cm squares. Bunch it in the middle with a rubber band or string and drop into ur yabbie tank. The more of these u use the more yabbie hidie spots u have. (Less fighting, food goes to putting on weight, not survival.)

They won't produce nutes quite as quick as fish, bc they just don't grow/respire as quick. A lot of what they eat is required for regular moulting of their shell etc. You could stack more in, givem some hidey spots and prolly get more nutes happening for ur plants. Fil and others know more on yabbies and will advise.

Closer to cactus dreamer?

yabbies prefer a slightly alkaline water. 7.5 is ok, but i wouldn't let it get lower than that.

yabbies don't like high conc. of iron and dont like COPPER AT ALL

Sorry, I should have answered some of the questions. The tank & grow beds are in the back yard, the fence is behind them in a southerly direction the grow beds have a shade cloth cover, no direct easterly sun as the shed shelters them. Northerly could be a minimal issue but the northerly fence would cut some of that 6 pm hot sun off on scotching hot days.
I have tried tomatoes, chinese greens, cauli, broc, strawberries and lettuce. My many attempts at gettting a photo onto the forum was unsuccessful. They are responding to both seasol, iron chelates. The other day I added a small dose of thrive with no immediate ill effects to the yabbies. Is this a potential problem? What else can I try without fear of disaster.
I added another 218 small yabbies the other day, ok so far.
I am actually closer to Streaky Bay, closer to Cactus than to Adelaide, Creative1.
Keep you great advise coming. Dreamer

Thrive - I think a collective shudder just went through all the Apers - thrive was used by a member which dessimated his fish colony (not sure of the dosage he used )

Try using seaweed concentrated Seasol if possible