Backyard Aquaponics
A place to discuss aquaponics

Thanks Tcl. I should probably buy the pump first and then get the outlet sorted afterwards... Abdul, it is easy to spot the naughty ladybirds. They will be munching on your baby marrow seedlings!

All the best to all my ap friends for the new year! To those of you being flooded down in Australia... My thoughts are with you.

Well its a new year and I have lots to do. On boxing day one of the remaining trout died. The temperature was getting up to 25 degrees so i decided to take the rest of the fish out.

I have noticed that the temperature in the tank drops considerably if a strong wind blows for a few days. Evaporative cooling i guess. this got me thinking perhaps i should construct some kind of evaporative cooler panel to keep the temps down. I was thinking of a matrix of pipes in a panel with shade cloth and some other kind of fibre to hold the water. along the top row the pipe has some drippers to keep the fibre wet. some of the water from the pump could then be fed through this. The whole contraption can hang over the fish tank and drip down into it. The wind is strong SE here all summer long. this way I could keep trout all year round. . Has anyone else tried this?

I have also put up shade cloth over all the grow beds. It helps lots but the wind and the heat are wreaking havoc on the poor plants.

Good to see you're still at it Brian
Happy New Year to you too.

Brian, that is an interesting idea. Have you thought about using a car radiator type design? If you have a radiator around, they should be able to cool the water off with a fan blowing over them.

Brian what you described is a type of "swamp cooler" - you may be able to find more info looking under that name.

Hmm... I would worry about the radiator as the ones i have are copper. Swamp coolers are for cooling down air, or no? I gather that the cooling effect that long periods of wind have on the water is due mainly to the evaporation of the water off the top of the fish tank. Assuming this to be correct would it make sense that increasing significantly the surface area for evaporation to occur would increase the effect . How about just suspending shade cloth from the fish tank roof and running water over it? As the water trickles down the cloth it partially evaporates cooling the remaining water that drips back into the tank. these could be stacked up in multiples for more cooling. Of course the problem would be if there was a long period of windless days. I guess if its very hot water will also evaporate from the cloth and cool. If only someone else has tried something like this out....

You have to be careful, though. They use a similar system here to heat up water. When they want to heat up the water, a black absorbing "tarp" is used for the water to run down. If you have a lot of wind, though, good for you trying to use it. Be careful to weigh the cost of water (could be high) compared with the cost.

I hadn't thought of the copper part.

The water is free so no worries there. I have installed 'cooling curtain' Mk1. it consists of a shade cloth folded double with a seam at the top. A pipe with holes in runs through the seam and wets out the shade cloth during every pump cycle. the water trickles down back into the tank. The temp was 22 degrees today. Only time will tell if this will work. I fear I may need to run another small pump to supply the curtain as it will probably need to run all day and night to really work. I also think that it may need to incorporate some sort of more absorbing natural fibre that can retain some dampness.

I had another idea although I fear it will be more expensive to run. To have a whole bunch of 2 litre soda pop bottles of water in a chest freezer that can be thrown into the tank to lower temps when they get too high.

I have had a good crop of onion. Probably 10Kg or so. The green peppers are doing well and so are the tomatoes. It is very hot here now and combined with the wind does not make for happy plants. I have been contemplating rigging up some micro sprayers on the growbeds. It may help to give the plants a bit of a foliage cooling off from time to time. Is this a good idea? I could put it on a timer and just give them 5 mins of irrigation a few times a day.

The cooling curtain is not very successful. if the pump runs all the time it does seem to help but the temp hit 27 degrees the other day. I have under advisement from the trout supplier decided to put trout in only in mid March, then I can run them through to December. I need to stock the tank a lot more this time. last time I put in 6Kg of fingerlings. this was 30 fish, but from a gut feel I could probably put much more in but how much is the question? I think I should get 20Kg of fingerlings and thin them out when they get to plate size.

I have been redesigning the system based on mistakes and problems encountered on the first attempt. I would like to start building this system soon and would appreciate any feedback on the design. Here it is

Hmm. I need to work on the drawing a bit. when I save it from cad to jpeg something goes a bit wrong. But you get the general idea... all in a line which makes for easier shading/ tunneling and also easier and more serviceable plumbing. it would also facilitate setting up multiple systems side by side. I am seeing four systems in a square area about 12 meters square. Four fish tanks 16 growbeds and four sump tanks. . Now just need to find that angel investor. Any super wealthy people out there who want to invest alternative agricultural research in poor suffering Africa.

I have recently been approached by a company doing eco tourism who want to bring people up to my farm to check out the ap system and the beekeeping, and sample the produce (the fish and honey mainly). I may need to create a beautiful outdoor dining area one day soon oh and have a really productive system

Ok. Here it is again. i hope it is a little more legible now.

Hi Brian,
Great system you have there. Nice onions, actually all the veggies look great. The sketch looks good to me and my limited AP experience. From my aquaculture perspective i was wondering if you have a way to completely drain the fish tank, so you can occasionally clean it. I couldn't make out some details on the drawing, so may have missed it. I am thinking you have an external standpipe/drain. I first saw drains like that at a National fish hatchery nearly fifteen years ago.

Also, on the few new concrete structures I have built, the pH always always jumps until it "ages" some. Unless you seal the "fresh" concrete.

Keep up the good work,
jd

One of my drains blocked up causing the bed to drain very slowly. I thought the kids may have chucked something down there but saw a few roots headed into the pipe. Small roots and only one or two. I cleared the roots but the pipe was still blocked so I blasted it with the hosepipe and the most amazingly huge pipe shaped root mass landed up in the sump. I was stunned at the size of it. About a meter long and thick and it all formed on a tiny 3mm root.

Wow, did you shoot a picture? Sounds like pretty good growth!

sorry for the hijack but what can you 'seal' the 'fresh' concrete with jd?