Backyard Aquaponics
A place to discuss aquaponics

and some more...

yum the fish looks delicious.
Whats that white stemmed green?

I think it is bok choi, the aphids love it along with the strawberries… got them on the run at the moment though

I think that Bok Choi has gone to seed and is probably bitter tasting now. Chickens would love it though...

Looks great Tom

Yes perhaps… I do keep a few things like lettuce at seed so I can collect them and replant… also we juice a lot of vegetables so a bit of bitterness doesn't worry me, just add some fruit to the mix.. we go through probably 3-4 litres of vegetable juice per day (some water added too).

The chickens aren't too fussy… they got a treat the other day when I hadn't noticed a ripe banana cluster and cut it down… probably 40-50 ladyfinger bananas for them

I have been having a lot of trouble finding any useful information on EC readings and their relevance to AP (not hydro).
I don't really care too much about them but since mine have steadily creeped up I thought it would be good to check if this is a bad thing?
They were originally around 600 or 700 us/cm which from what I read was fine.. but over a period of 6 months or so they have crept up to 2000+ which seems very abnormal from what I have managed to find out..

Ammonia has been kept at 0-0.25 for the past year.. pH has been between 6-7.. Nitrate almost always 0 !
I alternate lime and potassium hydroxide as buffers for pH.
I add iron 11% about 25g every month or so. (3000L of water in system)
A cap of Seasol every now and again.
I have never salted the system.

Growth Has not been as good the last 8 months as it was in the first few months…weird.. It seems like there hasn't been enough nutrients and my low Nitrate readings seem to prove that to some degree but then the high EC readings conflict with the low nutrient idea… I know that EC readings are a very broad indicator of nutrient solution but I wonder what could cause this?

Any suggestions from all ye brainy AP gods out there?

When you say EC in ppm, I guess you mean TDS? Electrical conductivty is measured uS, mS or Siemens/metre, and Total Dissolved Solids in ppm. TDS can be figured out from EC though, but I'm not sure how accurate it might be with all sorts of stuff in the tank.

I'll just pop down to my system and see what my readings are ATM.

Thanks that would be good to know.

I have one of these Ebay cheapies:
http://www.ebay.com.au/itm/EC-Electrica ... 514&_uhb=1

It says it measures:
"This EC meter is a device to measure the electrical conductivity in a solution with measuring range 0 - 1999 μs/cm"

It actually blinks if I put it in the water now which means it is above 2000 US/CM
I have tested it in tap water also and it seems to work since it shows a low reading there..

Currently in my FT:
pH 6.73
EC 1894uS
TDS 1.34ppt
Salinity 927ppm
Temp. 9.9C

Just looking back through my log book I also have:
8/6/2013
Salinity 213ppm
TDS 318ppm

9/6 added 4.8kg salt

10/6
Salinity 985ppm
7mm rain

11/6
Salinity 965ppm
TDS 1.33ppt

So, TDS is about the same as 11 months ago.

Well it seems your EC reading is high like mine… well at least I am not the only one
maybe some others will do some tests too.. would be interesting to see others levels.

So TDS and EC are just different measurement units of the same thing or?

Do you add salt for the fish health or other reasons?

EC and TDS are different things, but you can determine TDS from EC in some cases, is my understanding.

I added salt for fish health when I put the trout in, 1ppt to start, but a week later I discovered they had Ich, so increased it to 3ppt. Since then I've removed water to water some trees when it was particularly dry, overflowed a bit from the ST a few times when making up evaporative losses at low tide instead of high tide, added tank water, and rain has fallen into the system, to bring me back to a bit under 1ppt.

EC is fairly directly related to how much salt you have in your system. That 318ppm in my system before I added 4.8kg of salt was mostly salt from the Canna clay balls. That was only from the 10 or so bags I'd used in my GBs (mostly gravel) at that stage, when I was running a bit less water than now. I think I calculated and made a comment in my system thread early on about how much salt must have been in the clay balls.

My tap water (all rain water from roof) has: EC 7.9uS, TDS 5.6ppm, 8.0ppm salt.

Tom did you install a window on your fish tank?
Can you show us the process and some pictures

Funny you should say that but I did install one just the other week and did take pictures of the whole process which I will be posting. I have just been holding of until I had a chance to take a video of the fish in the tank with the underwater lights in.. also I have to wait to get the pictures of the camera I used as I have left it at my parents place.

But soon I promise

Well I took some video of the fish through my new window. I have 2 x LED 12v strips in there as well which light it up quite well. Since I have a GoPro and it is water proof I added some in tank video… the water is pretty clean these days after adding some filters I made between the GBs and Sumps…
I also have some photos I will add of how I built the window.. nothing very new as it has been done before but it may interest some of you!