Backyard Aquaponics
A place to discuss aquaponics

Thanks Charlie, I have been watching that thread, but as yet, the question is still unanswered.

I could be wrong, but I think the way to test would be to check the nitrates coming into the bed, and check them again as they leave the bed, if they change, then the flow might need to be increased.

Also, check the dissolved oxygen (hard to test, I know), if the levels are lowering too much, then you'll have growth problems.

I found when I had the gravity feeding from bed to bed, before I upgraded the pipe size (one bed would overflow before the water would travel to the next), it wasn't giving great growth. Since I upgraded the pipe size, the growth seems to be far better. But each system is different, so I don't know how it'd affect you.

I had my first little set back yesterday.
The wind picked up during the day & flipped upside-down, one of my fully planted rafts. I got home to a tray of dried roots & withered plants, which have not recovered in the slightest. A few of the plants on the raft it landed on were also damaged. I will have to thin more seedlings from the GBs & replant tomorrow.

The strawberry runners I put in the DWC last week, have powered ahead & have shown no signs of stress at all. They have a bunch of roots which are now about 25mm long (they had no roots at all when planted). In comparison, the runners I put in the WB are dismal - all wilted & miserable.

Hi Colum, I don't have access to a DO meter & I am not inclined to buy one at this stage. The N03 measuring might be okay...if I had any!!! I think I will just have to wait & see how things go.

Things are ticking along nicely & I love being home poking around in the greenhouse.

I took the long trip to Tooperang & bought 100 trout fingerlings (30 for a friend) last weekend & barr 3 jumpers, they have started eating well. I had to make a much closer fitting lid so they couldn't find any gaps!

I still have no Nitrates & the pH is around 7.4 so is slowly coming down. We no longer have any dam water so I am topping up with rainwater now (lucky 3 out of 4 kids have left home so water is not so critical), although the land is desperate for rain.

The growth in the GBs is better than the DWC, but that is to be expected as the DWC seedlings were transplanted & disturbed. Having said that, the strawberry plants are going well & some of the celery is starting to take off.

The bath tub system is producing bucket loads of basil, tomatoes, spring onions, chillis, kale, beetroot & zucchinis & the broccoli is just sending out side shoots after harvesting the main head.

The capping for wicking beds has been made & attached & I just need to add mulch to raise the level & hide the builders plastic & geo-fabric - I am just waiting for seeds to germinate.

Turn over for a DWC can be from once per hour to once every four hours,i have ran once per hour and once every two with no difference in growth.

Thanks for that Dasboot - I have a serious problem then!
My water is going through much more slowly than that - possibly only 150lph in a 1300l bed. I am using my spare pump on this system, so maybe I will have to buy a bigger one to get the turnover happening.

Love the growth of your greens, very jealous. Keep up the good work!


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Thanks Ben. I have been adding plenty of seasol, & have also added iron chelate & magnesium as new & some older leaves were looking pale.
With 70 trout fingerlings around 6-8inches long, I am not yet registering any Nitrates even though they are fed twice a day & smash a heap of food. I haven't planted much in the GBs yet - just waiting for a tiny reading of N03!
My bath tub system is the same & that has 60 larger fish.

Most things are powering along, still without any N03. The plants in the media GBs from the hybrid system can almost be seen growing - amazing to see every day. The same plants (pak choy & rocket) in the raft are quite pale & nowhere near as big. I added a good teaspoon of iron chelate a fortnight ago & things improved, but leaves are yellowing again. I have doubled the iron dose today, but am not sure how long it should be effective or am I overlooking something else. I am reluctant to add calcium (thought this may also have been deficient) as my pH is already 7.4 but if anyone can offer advice, I would be greatful.
The picture is of pak choy.

My second issue is the strawberries in the bathtub system. Some of the leaves are also yellow, but all other plants seem fine. pH is 6.2-4, the highest it has been in years. The plants are all still shaded (50%) at the moment & I have wondered if the strawbs had a light issue.

It looks like potassium or magnesium deficiencies to me.

Grab some seasol powerfeed, or Charlie carp, it should set it right.

Hey Team41

Maybe this link might help?

http://asktheplant.com/?p=67

I think I read that he have been adding SeaSol magnesium potassium

Looks like classic iron deficiency to me. Are you adding Fe?

I had the same problem a while ago, sorted by iron chelate foliar spray once weekly. Took almost a week to improve.
I've never had nitrates in my system either. Starting to think the test kit may be telling pork pies...