Backyard Aquaponics
A place to discuss aquaponics

You could also add some nutrients via a fish / seaweed extract, not everything that plants need is present in the fish food.

That's a good idea, anything from the sea has a lot of trace minerals and other nutrients, right? Would adding a solution of seaweed or fishmeal powder to the growbed work as well?


14th of June (feeding 15g a day):
pH: 6,5
NH3: 0,2
NO2: 0
NO3: 3,0

Today (feeding 30g a day):
pH: 6,2
NH3: 0,1
NO2: 0
NO3: 1,0

The pH is low, but as far as I can tell from these values the bacteria are doing fine. I hope the shells in the GB keep the pH from going any lower.

I just add my seasol to the water, and I would definatly add some more seashells (washed) to the return line as well with a ph like that. You probably want to start it trending up now, before it does get lower.

For some reason my PH has never dropped, I have a small amount of shells buried, but may be due to the media.

Got three more fish (~17cm; one koi carp and two koi x grasscarp hybrids), and slowly giving more food per day. The strawberries are doing great, or at least better than they ever did in soil.

14th of June (feeding 15g a day):
pH: 6,5
NH3: 0,2
NO2: 0
NO3: 3,0

28th of June (feeding 30g a day):
pH: 6,2
NH3: 0,1
NO2: 0
NO3: 1,0

3rd of July (feeding 45g a day)
pH: 6,6
NH3: 0,4
NO2: 0
NO3: 2,0


The pH has gone back up a bit with the shells in the GB, but I think it's still too low for the bacteria to keep up with the new fish. The ammonia hasn't been this high since I added the first fish to the pond.

I'm going to get 5 big koi carp (40cm) this Sunday , which means I will have to feed 3-4 times as much as I am now, soon. I'm counting on a big ammonia and nitrite spike after adding the fish, but hopefully with a bit higher pH (more shells?) the bacteria will catch up pretty quickly.
Any advice?

Didn't change anything, but pH went up to 7,0 - which is good. Could be because of measuring at different times of the day though.

I got some sodium carbonate decahydrate (couldn't find any potassium bicarbonate or even sodium bicarbonate) and tested 3g/65l -> pH went up to 7,5. I only want to change pH about 0,2 (to 7,2) so I added 20g to 65L of tap water and added that to the system. The fish don't seem to mind, will test the pH again after a couple of cycles.

The plants are clearly benefiting from the increased feeding; three watermelon seeds which germinated weeks ago and had been just sitting there actually started growing leaves. Still, plant growth is terribly slow (except for the strawberries which are doing great).

xzorby - baking soda is sodium bicarb!

I know, but thanks anyway. I asked if they had any at the supermarket but they didn't! But this is only for getting the pH up on a short term to get the system cycled faster when the big fish go in tomorrow, so I just got the sodium carbonate which I knew would work too.

Some of the plants in my system have a potassium deficiency, so I'll try to find some potassium bicarbonate soon.

Yay, we got some really big fish! They're four ghost-koi, 35-40cm, and I'm getting one more before the end of the week. I also got some more small carp (15-20cm). They all seem to be doing fine, and so does the water quality. Plant growth is not exactly spectacular; only the strawberries are actually growing well, but with those new big fish I expect that it will change soon.

6th of July (still feeding 45g a day)
pH: 7,0
NH3: 0,2
NO2: 0
NO3: 3,5

The three biggest koi (new ones), together with a bunch of other (koi) carp, goldfish, rudd (black with red fins) and ide (the two small blue fish). Also a slightly smaller but still pretty huge (compared to the others) new koi in the back.

Two of the new guys.

They're beautiful fish!

One of the smaller carps I got last week - probably a ghost koi x grass carp hybrid - together with two of the goldfish.

Better view of the fish.


Also a nice video of the fish: http://www.youtube.com/watch?v=ha8BndBtUsc

The first Monarda Didyma (beebalm) is flowering. The wind almost blew them over as you can see in the back, but they're not damaged.

Strawberries doing great.

More strawberries (and some sorry basil).



The guy I got the fish from is very interested in seeing my aquaponics system and maybe wants to build one himsef. His pond is as big as mine, and absolutely full with koi carp. His water is dark green with algae so you can't really see anything that's more than 15cm deep. He hopes that an aquaponic growbed would help remove nitrates and make his pond clearer, and he also likes the idea of growing strawberries and possibly some other things.

Once he sees your system, he would be converted I think. Great water, and they are some angry looking fish

Your first AP convert Thomas.....

And love the size of those fish man

Looking good Thomas!

How's the sunfish doing? I've had one in a goldfish pond a few years ago, but I had to take him out because he was constantly chasing the goldfish and managed to take quite a few bites out of the goldfish tales and fins.

Thanks! The sunfish is doing fine, and not chasing any other fish (yet).

Yesterday the last of the fish went in - the biggest of them all. A ghost koi like the others, but even bigger (40cm). The fish was all white of stress when she (he?) went in, but the dark colour has come back almost entirely now.

Just now one of the smaller blue orfe started acting strange and floating upside down. I think there's something wrong with his swim bladder, because he can still swim normally but it takes up more energy and when he doesn't move he starts floating upside down. I put him in quarantine with 100g/33L salt and antibacterial stuff. He's only 12cm so I doubt he will survive, but other than floating and being white from stress he looks fine...

One of the big koi has a small spot of fungus and another one has some other sort of spots that appeared after they went into the water. They probably have parasites. They're eating well though, and apart from the few spots they look healthy so I'm hoping they'll recover.

6th of July (feeding 45g a day)
pH: 7,0
NH3: 0,2
NO2: 0
NO3: 3,5

12th of July (feeding more)
pH: 6,5
NH3: 0,3
NO2: 0,8
NO3: 5,5

Added another 40g of sodium carbonate decahydrate to get the pH up a bit. Hopefully the nitrite won't rise any further, because the day after tomorrow I will be gone for at least a week, probably even a month. Bad timing

Yep, changes to system are bad, just before leaving it

Your major ph changes are bad too

Outbackozzie, the pH swing is probably because of the massive amounts of (acid) rain we've had over the past week or so.

13th of July (feeding a bit less again):
pH: 7-7,5? (test fluid ran out, inaccurate)
NH3: 0,1
NO2: 0,4
NO3: 3

Ran out of the first kg of fish food, so bought some more. The biggest pellets are too big for all but the new carp, but the smaller fish still try to eat them. I think that maybe the fish that began floating upside down yesterday (still alive, by the way) might have choked on a big pellet and damaged his internal organs or something..

Another big bag of washed sea shells would probably be a good thing to help stabilize the pH for while you are gone. Bust them up small if you can to get more surface.

The bigger pellets can probably be crushed up or busted up a bit so the smaller fish can eat them, the big fish will still be able to eat the smaller bits.