Dui's 8000 litre system

DuiNui

After a reasonably successful start with a mini system, I have started to build a decent size system.

Fish Tank and sump tank are 2mx2mx1m
They are made from concrete blocks reinforced with steel on every course, I wanted them round but couldn't find anyone here confident that they could build a round tank.
I couldn't find anything to seal the tanks with that was guaranteed safe, also no one here seems to know about EPDM liners, even though I know it's made in Thailand, so the insides of both tanks were tiled.

The growbeds are becoming a real pain, I told my builder what I wanted to achieve and he said that concrete would be the quickest and cheapest solution, but it is taking forever, costing far more than I originally thought and is starting to look like a car park !

I was going to build 3 like this but I think I will stop after this one is finished and try again with welded metal stands.

I wanted growbed area on top and shallow pools underneath for Freshwater prawns and duckweed, I think it will be ok, but it looks so crap !

More pics soon but progress is slow at the moment.

faye

It is a construction site in progress, don't jusdge yourself so harshly just yet. I think you will find that when all the formwork has been removed and the beds are overflowing with lush green growth it will have been worth the effort. Renovations in progress can be a little overwhelming at times. My advice is to take plenty of before and progress photos and look at how far you have come. Good luck and thanks for sharing with us.

DuiNui

Faye,

Thanks for the reply and encouragement

More pics... forms off, still looks like a car park though, and so much concrete, it's probably stronger than one.

Had my first major setback last night, we are entering the rainy season in Thailand and last night's storm was exceptional even for this part of the world.
The garden was nearly 2 feet under water, more storms like that and I may need to park the car on the GBs

Result: Flooded sump tank full of silty, sandy water.

On a positive note though, the tank is now full of bullfrog eggs, if you look closely you can see hundreds of tiny black and white eggs.
Best that it happened during the construction phase than with a tank full of fat Tilapia!

Hopefully the builders will turn up tomorrow and finish the first growbed, they wanted the day off today as they were out catching bullfrogs all night last night that turn up in their millions with the first real rains.

They are a delicacy here, especially the females who have eggs, I just tried eggs and some legs, it's true the legs do taste like chicken, but the eggs were a bit like fishy liver, not really my cup of tea, but interesting to try.

Cheers for now,

Dui

welshdragon

Dui

If every project went according to plan then life would be very easy,very boring and we would learn nothing. We will watch your progress with bated breath and as Faye says that when everything is working,and it will, all the problems will be very small.

Keep going.

WD

Simo

From the looks of it this is going to be an awesome system when finish.

Are you going to raise the sides of the ST or improve drainage so the flooding issue does not happen again?

Keep up the good work.

TCLynx

Yep good thing to discover now. The flood danger that is. I hope there is a reasonable way to protect the system from flood like that again.

At least with the concrete, you won't have the stands rusting away in a couple years as things tend to do in the wet tropics.

Hang in there, construction sites always look bad.

DuiNui

Hey all,
We added 2 more courses of blocks and dug some trenches to keep any flood water away from the sump, fingers crossed.

First row of growbeds nearly finished.

And so the gravel washing starts.
This was the first wheel-barrow load, she won't be smiling after 500 of them :shifty:

I am having a nightmare with the liners I got for the GB's, they are thin and peirce easily, I am tempted to just tile the GB's now too.
Hopefully I'll get the plumbing finished today, we're getting there

Cheers for now.

DuiNui

Hi all,
Things have been very slow but we are finally making some progress.
After 3 months of looking for a suitable tank/GB sealant, I found exactly what I was looking for.
It's called Crocodile Flex Shield, cement based, non-toxic flexible water-proof sealer suitable for drinking water tanks.
I was having a nightmare with pond liners, they are very poor quality here, so I'm very relieved to find this sealer.

Some more pics:

Plumbing nearly finished.

Pumping into the FT

I already added the 5 fish from my mini system as that was proving to be very high maintenance, so I took it offline
and used the gravel to prime my first proper GB.

Then I was offered a deal on 1500 catfish and 150 Tilapia which I simply couldn't refuse.

I was going to put them all the the FT but the guy I got them from said the catfish would eat the Tilapia,
so I had to make a snap decision and put the Tilpia in the sump tank.
I'm regretting it now, keeping things clean is becomming tricky, I really should have waited before putting
fish in there, and certainly shouldn't have taken the Tilapia, but there we go.
We have lost a lot of the Tilapia, at first the red ones (Bpla Tab-Tim in Thai) were dying at a rate of 4-5 a day.
None of the green ones died which seemed odd to me.
Since then we went perhaps a week with no deaths at all and then the green ones started dying, again 4-5 a day, maybe more.
We're probably down to about 50 from the original 150.
The people at the Ministry of Fisheries said we can take some live ones there and they will try to find out why they are dying.
Trouble is, I can't catch them, way too quick for me.

Water tests (both mine and the Ministry's) have shown no problems, Nitrites are high, but they said that wouldn't cause all
these deaths, without a live fish to look at they have suggested the fish were sick when we bought them, which could explain
the "too good to be true" offer.

Today I have decided to do a 50% water change on the basis that it can't hurt.

Heres' a pic of the FT with the Catfish, 2 Bpla Dapian (not sure what the English is for those 2, they look a bit like Chubb)
and 4 Bpla Mor (look a bit like Perch)

The rainy season has started here and with the rains come millions of bugs, I left the small light over the tank on over night one
night and this was the result:

Feeding the Cats shouldn't be a problem with this many bugs around, drawback is the water is very dirty within hours of them being
eaten and thick with the uneaten wings.
I have decided not to feed them these again until I get the SLO's working better, I am spending way too much time manually cleaning
the FT at the moment.

Last pic for today:

First signs of life from the GB.

Cheers for now all, am about to go and put a second coat of sealer on the second GB.

Dui.

faye

Good to see that you are still at it Dui! The bugs will provide a great source of live protein, ooh so many though.
You must be on the home stretch now, and I hope you helped with the gravel washing!

rmcpb

Just loving this system and the contrast to here. Freezing here at present, ice on tanks and growth nearly at a standstill although the silverbeet and peas are making "progress".

I agree that its a construction site so don't judge your builder too harshly.

Now keep the posts coming

gemmell

DuiNui wrote:

Water tests (both mine and the Ministry's) have shown no problems, Nitrites are high, but they said that wouldn't cause all
these deaths, without a live fish to look at they have suggested the fish were sick when we bought them, which could explain the "too good to be true" offer.

Today I have decided to do a 50% water change on the basis that it can't hurt.

Did you do Ammonia and Nitrite tests? What about pH levels? As you say, could just be sick fish to start with.

Do you know about salt (NaCl) being a good tonic? Maybe you should dose to 3ppt and see if it makes a diffrence.

DéjàVoodoo

I love concrete systems! I think your system looks spectactular!

DuiNui

Hey all,
Thanks for the compliments

Gemmel,
I did know about salt (thanks to this forum), but completely forgot to do it, have now dosed to 2ppt and have only lost 1 cat and 1 Tilapia since and none for the last 5 days.
Thanks for the reminder, I feel a bit stupid forgetting that one!

My PH is high at around 8.5 but we are entering the rainy season here so water top ups to the sump are going to be rainwater.
I tested some rainwater and it has a PH of 5, so hopefully over the next few months I will see the PH drop a bit.

Some more pics:
Second GB sealed and ready for gravel

Two GB's up and running:

The Cats

Both Catfish and Tilapia growing well now.
Have planted lots of different things as an experiment to see what grows well.
I have put some rice seeds in together with some rice plants at various different stages of development.
It'll be interesting to see how the growth compares with the paddy field rice.

Next on the list of things to do is get the 3rd GB sealed and online and then build another row of GB's.
The single SLO I have in the tank is unable to keep up with the pump , so I had to buy another smaller pump for now.

Cheers for now

Dui

DuiNui

I seem to be having trouble with high Nitrites.
Water tests show:
Ammonia: A trace < 0.25mg/l
Rites: 1mg/l
Rates: 12.5mg/l
PH: 8.5
Temp: 30 degrees.

These figures have been consistent for some time now, the Nitrite levels do not seem to drop.
I have been feeding the fish fairly heavily until now.
Have decided to stop feeding for a few days to see if I can get the Nitrites down.
Seems I have a lot more NH3->NO2 bacteria than NO2->NO3 as no matter how heavily I feed the fish, I never have more than a trace of Ammonia.

Am I doing the right thing by stopping feeding?
If so, how long is it safe to stop feeding for? These Cats are mostly about 3-4 inches long.

TCLynx

Most fish can survive quite a while with little/no feed (exceptions would be tiny fry or fish that will eat each other when hungry.)

I would say let them be hungry for a few days and see if the nitrite drops for you. Generally the nitrite spike is harder to get by, especially with the high pH but once you get past the initial spike, things should get better.

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