Backyard Aquaponics
A place to discuss aquaponics

Nh4 @ 0.25 is okay, but NO2 will be zero once you are cycled. Keep a close eye on it, as NO2 is the fish killer.

I see. Thanks for that one.

I find the info that one hits with google regarding those values rather conflicting.

I am no good really with the NH NO business, I prefer to use their long names, so I will just to make sure I am giving the proper info. .25 for ammonia is okay, my system usually reads somewhere between zero and .25. Nitrites needs to be zero, in a cycled system you should have a pretty blue test tube from your test kit. Nitrates can be safely way the heck up there.

Nitrites are now 0 and nitrates runs very low between 1 and 5.

Would like to see if the few small fish can produce enough nutrients in winter. They are are now feeding less with water temperatures between 16 and 20°C. I think the water may drop another 5°C or so in the next few weeks.

Sent from my GT-I9500 using Tapatalk

Hi Koos, yes our temps are also dropping here in JHB but I think Bloem is a little colder than us in the winter. What are your minimums, how cold does it get?

Regards, Martin.

We typically gets daily minimums below 0 in mid winter. -5°C is quite common when the teeth comes out.

Sent from my GT-I9500 using Tapatalk

Thanks Koos. We're usually above 0 but go into the minuses during cold fronts, usually -2 to -4. The coldest we've had since we moved to JHB in 2006 is -8. I remember driving to work that day and the council had left some sprinklers on by the roadside and the banks were covered in icicles and ice crystals on the trees it was quite spectacular.

Regards, Martin.

Not sure if you fixed this but I use picasa/google+

When you paste the link like this


take note of the w835-h555- part - which you can just change to another number (in the below case - I changed the w (width) to 250 pixels

Been very busy at work the past few weeks - hence no time for posting.

About 3 weeks ago I had a first load of granite delivered and replaced 7 of the 16 buckets of peat with gravel. I will do another part later and then the rest - to ensure that the biological filter does not get a shock.

I then moved over some plants from the original cocopeat and most of them took in the gravel, but some still have a bit of shock.


It makes for interesting comparison.

1. It does look like the gravel makes the plants grow better and that it is a long terms media.

2. The most surprising though was that the buckets with the good cocopeat flows any time as much as the gravel. The buckets with the bad cocopeat just becomes pulp.


The drawback then of cocopeat is that the media is not consistent and I can see the worms are hard at work in there, degrading it over a matter of weeks. It won't last 2 years unless only used for seedlings. I am glad through that I tried it. There is a place for it in the system.


The koi fish are doing very well. I now have 80 of them in the dam.

Ammonia running 0
NO2 is 0
NO3 is about 2.5 right now.


PH changed from 7.8 to 8.2 after adding the granite. A tad too high for my liking but right now I am not concerned as NH3 is well within limits.

We had a very cold week in Bloem with water pipes twice frozen up in the morning and water temperature drops to 10⁰C at night with no heating. It rise to 14⁰C at day. I will now experiment with harvesting heat from the greenhouse during the day - will show details of that system later. But it will be MUCH more powerful, compact and cheaper than solar. I believe I will easily raise water temps even in this conditions by 5⁰C at night and low electrical input.

My plants are going well. The greenish leaves are basically gone and the baby marrows already gave us fruit each week.

That said, the baby marrows are the only plants that suffers heavy from mildew on the leaves - and our conditions at night was perfect for that problem. I still need to find a good solution there but the teatree oil spray did not work too well.

It may mean that I could decide not to do baby marrows during these few months and only in summer.

The greenhouse skin kept the frost of the plants and even with greenhouse temps at 0⁰C the leaves did not suffer significant damage. I am happy with that. If the water pipes freeze up and the plant are OK, I think the chances are slim that I will suffer frost damage in future.

Some more pics.

Looking good! You are correct in that the coco peat was not a waste, it is FAR easier to start seeds in it. I use it in seed starters on top of capillary matting.

Thanks for the detailed update Koos. Your changes look great and I think that you will go from strength-to-strength.

Regards, Martin.

I see I was here a long time ago and as usual, because of my day job.

I patiently had to work through many obstacles but I think after yesterday the last of my major problems are solved.

A Quick summary:

1. I found that the Baby marrows does not do well in winter and the leaves get mould. This can only be solved with some heating at night and I will rather just not plant baby marrows in winter.

2. When the fist tomatoes came out just at the end of winter, I found that something was eating it and soon realised it must be rodents. AS much as I hate it, I had to throw out rat poison, but kept it to a brand on our side that kills the rat only and not dogs or owls that may feed on the dead bodies.

3. We also had some serious wind which half took off the roof sheeting one day when I was away and I had to replace that last weekend. I will do another mod to prevent that from happening again, but the problem is as said before, that my roof is not a dome roof and that does make it impossible to get the required tightness. In hindsight, I probably should have made the roof with 3 stepping angles.

4. I replaced all the cocopeat with gravel, accept for two beds and having had the peat and granite together, the plants did much better in the granite - until we hit summer that is. It also gave the system a bit of a shock to get the bacteria population established. Nothing serious though and I did not loose any fish.

5. In the hot weather, I suddenly found my plants got heavy damage from heat and at first I thought ventilation could be the problem but it was not. I thought that I might have to add shade net on top of the green house film. It was only one day when I got home early that I found the top layer granite gets EXTREMELY hot and that is where all the damage came from. It basically damage the plant right at the bottom and fries the leaves with radiation.

To solve that problem, took a bit of thinking to get a simple solution, but I think I got it. I have installed a pump timer yesterday that simply switch off the pump every hour for 15 minutes from 10:00 to 16:00 in order to flood the growth beds completely and by doing that it cools the rock. The pump takes a further few minutes to drain the beds again to normal level. That way I think most of the heat stroke will be solved.

The earthworms does surprisingly well in the granite which had plants in.

At the moment, I am monitoring the algae growth in the pond, and the kois are feeding well on that I don't feed them other food. In spite of that the NH3 stays a little pink and I will start feeding them again when I see the system needs it.

I would have like to post some pics, but I remember I had a hard time last so please just forgive me for not trying again.

I currently have tomatoes, peppers, spinash, beans and corriander. The plants are still smallish and I need to see if the damage from the heat will be reversible. Hopefully I caught it early enough.

So far I found the playing to be a great joy and I came to appreciate what plants are all about.

Thanks for the update Koos. Good to hear from you and to hear of your progress.

Regards, Martin.

Some more updates.

https://www.dropbox.com/s/gx9xm29qxfwft ... 2.jpg?dl=0

https://www.dropbox.com/s/rt2b7ilb75zoy ... 1.jpg?dl=0

https://www.dropbox.com/s/fb2gy2vbu9cll ... 9.jpg?dl=0

https://www.dropbox.com/s/63yvkwkoa8kn5 ... 6.jpg?dl=0

https://www.dropbox.com/s/0vtqye2z826in ... 8.jpg?dl=0

https://www.dropbox.com/s/nl413ri2te153 ... 7.jpg?dl=0


I could spend a bit more time in the tunnel lately and I was confronted with some more problems.


Back when I had both the Cocopeat and Granite to compare, the plants did quite a bit better in the granite, and I eventually switched all the media.

Great was my surprise when the plants now suffered tremendously and simply could not grow big. Fish are doing excellent though. Have not lost one in months.

The PH went up when the cocopeat went out. Quite surprisingly I would say as I tested the granite before in RO water to see if it swings the PH significantly and it did not. So, high PH (9 most of the time) and high water temp obviously creates a very thin margin for dangerous ammonia levels. But the system cycled easily and ammonia, nitrate and nitrite are all zero.

My conclusion was that the higher water temperature had quite an influence on the availability of oxygen in the water and I added an oxygen pump. Slight improvement and the leaves on most plants got a nice dark green again, but the plant growth was still poor and I could see that the plants did not really grow much roots.

I had to solve another problem too. With our country currently suffering from electrical load rolling, I had to make a plan to have the flow stop by itself when the power goes down. I looked at may ways, but all were rather expensive, so I did something else...

To resolve this problem, I installed a 3-speed inline Wilo pump that lifts the water to above pond water level. If the power goes down, the flow stops as the raise was selected such that syphoning cannot take place. It is running constantly, but at 50W consumption it ain't too much of a hog.

This also gave me the chance to increase the flow to the growth beds as it seems to be a problem. The 3-speed pump works wonders and is running on speed 2 with the flow that increased to about 3 times it was before. I did had to dig in my sump though because the water could not drain fast enough. The sump can now drain water even with the pump on setting 3, so I could add some growth beds in future.


Further plants observations:


1. Tomatoes and spinach are definitely the toughest and did better overall.

2. The pepper suffers quite a bit and the leave are curling. See many people have trouble with them.

3. Could not manage yet to let the cucumbers to grow nicely.

4. The mint does well.


Once again, waiting again to see what difference the increased flow makes. If I had more time, it all would happen a bit quicker but I am far from loosing patience.

And I had no green finger what so ever, but my understanding of plants improves all the time.