Backyard Aquaponics
A place to discuss aquaponics

I just read your post to me on AAs thread. I was busy here posting to you.

Yes, I was lucky to spot the plastic peg board at 'Home Depot'. It is stiff and does a great job of supporting media in a filter. Of course if you like drilling your own holes....? Actually, it is always better if you can make something you already have work. Buying two peg boards set me back $25US. I have spent way too much! More junk yard and less stores would have saved a bunch.

I saw a DWC system in Alberta, Canada (they called it Deep Flow Technology [DFT]). Dr. Nick Savidov had this system working beautifully with Tilapia and many kinds of plants in a cold climate like mine. It was that experience that moved me from my plan to do an S&S Aquafarm F&D system with pea gravel to DWC (I even bought the gravel before I switched). The DWC system has a drawback that I will evaluate. That is the susceptability to pythium developing in the roots of long term plants like tomatoes. I will stay with DWC until I have a problem. If I have pythium problems, I will switch to F&D gravel. My growbed will work either way.

I got a GH and KH test kit on the weekend and tested the water this morning. The pH had been low (got down to 6.4) but it was back at 7 today.

I have put about 1 1/2 cups of shell grit into the system and this seems to have worked. The GH was 11 and the KH 4. I tested rain water (it was 0) and bore water (GH 27, KH 11) just for fun. I would add some bore water to increase the hardness but it is slightly salty (1400ppm) so I don't think I should.

Still need to get the plant side of things setup, the nitrates are up to 30 - 40 ppm.

Nova

Nova,
1400ppm for the salt would work out to 1.4 ppt, right? That's a nice theraputic level of salt for fishies, and wouldn't bother most plants. I wouldn't worry about supplementing rain water with bore water.

Of course, if it ain't broke, don't fix it.

Here are some pictures, one of the fish and one of the larger shellgrit bits on the surface of the gravel (the smaller bits have fallen down the gaps).

Hi Janet, I have trouble growing strawberries in my garden because of the salt in the bore water. Maybe I am being a bit overcautious, I may add some next top up.

Nova

I reckon Big Mick will have a few snivvels when he see's his beautiful goldies LOL

Yeah, they are ripper fish. One died last weekend, so I am down to 12. I may have to get them some friends. That reminds me, I still haven't put some of the catfish in with them yet. Must put it on the list for the weekend.

Nova

Well I got the Tandans in with the goldies on the weekend and they seem to be doing fine. After keeping to the bottom of the tank for a couple of days they now actively come up nearly to the top after pellets when I feed. I now need to put a bit of feed in at once so the goldfish don't eat it as soon as it hits the water and there is some left slowly sinking for the catties.

I haven't tested the water lately, but it is still nicely clear (did I mention that translucent tanks are bad for algae problems?). I added a couple of silverbeet in small netpots floating on the surface where the bubbles from the venturi are. They are still small, but hopefully remove some nitrates soon.

[edit] changed statement about translucent/opaque tanks as I had them mixed around [/edit]

Nova

Intersting thought on the opaque tanks Nova, hadn't really thought about it, and I know someone who's just set up a system using one... Might suggest they try and paint it or cover it in some way..

um.......opaque means "impenetrable by light; not transparent or translucent."

oooppppssss...... I always get that wrong....

And viscous, I get that wrong too... Is more viscous, more like a liquid, or is less viscous more like a liquid?

high viscosity is very liquid.

just on the opaque thing. did u get it wrong too nova? i've found that black works much better than translucent.

Hello Steve.

High viscosity means thick like syrup. A low viscosity oil is thin. Actually, viscosity is more a measure of resistance to flow and high viscosity means high resistance to flow. But thick and thin usually follow.

Being an engineer in 'auto town', you hear a lot about viscosity.

see, i'm fallible too! LOL

thanks for the correction! i was going to google it first but i thought i was sure! Obviously not

hahahahahaha.......... Tricky bloody words......