Backyard Aquaponics
A place to discuss aquaponics

Everyone,

I started my first aquaponics system this past November in my garage. I am using a 50 gallon plastic storage container for my tank. I have two slightly smaller grow beds that flood and drain into two small raft systems. I only have plants in one of the raft systems. (I am using hydroton expanded clay pellets in the media beds.)

The tank has a couple small Koi and and maybe 30 - 40 small goldfish.

After about six weeks, I was able to get the system cycled, and was growing plants without any problems with the fish or plants.

Three weeks ago I moved the system outside so that I could give the plants actual sunlight. It has rained an unusual amount over the past couple weeks. In the first storm some rainwater runoff from the roof went into the tank. Since that time I have blocked the vast majority of this type of runoff, but there probably is a little still getting into the system.

The second media bed and the second raft bed was added to the system three weeks ago when I made the move outside. (It had been One media bed and One raft bed.)

Since moving the system outside, algea has grown in the raft bed. There was NO algae when the system was indoors. There is NO algae in the fish tank (which is not in the direct sunlight.)

For about the past week, I have been losing 1 to 3 fish a day. This is the first that I have had this problem. Thinking maybe the fish were not getting enough oxygen from the water being returned from the grow beds, I added an air pump and air stones earlier in week. This has not seemed to have made any difference. Yesterday I tested the water to see if maybe some level was out of whack.

Water temp - 75 degrees
pH - 7.4 - 7.6
Ammonia - 0 - 0.25 ppm
Nitrite - 0 ppm
Nitrate - 0 ppm (This REALLY shocked me. Nitrates had been between 80 - 160 ppm before I moved the system). Is it possible that the plants are absorbing ALL of the nitrates? It seems to me that if somehow that tank has become "uncycled," that my ammonia level would be off the charts -- which it clearly isn't. Outside temperatures have been between mid 50s to upwards of around 90, so I don't think that should have killed of the nitrates.

Since I moved the system i added the second media grow bed and second (unused) raft bed. The plants seem to be growing fine, but the fish are clearly having problems.

After reading up on this yesterday, I ordered a GH and KH Test Kit which should arrive tomorrow. I those levels seem in check, does anyone have any thoughts on what I should do to stop the fish deaths? With the added plants, I THINK I need to increase the number of fish in the tank. I hate to do so, however, until I can nip this problem in the bud.

Any thoughts or suggestions would be greatly appreciated.

I tried to include all of the relevant facts I could think of. If a picture of something in particular would be helpful, I will try to take and upload one.

Thanks,
Doug

Just off the top of my head I'd say water temperature fluctuations are a likely candidate. The grow beds act like heat exchangers so even without the tank in the sun that could be a problem. It's also possible you had something from the roof that was toxic or a nitrite or ammonia spike and didn't know it but are still seeing some deaths related to this. Seems like quite a few fish for such a small barrel, you're probably OK for now but but keep it in mind on down the road.

..
I just killed all my fish, virtually overnight..
There were no water readings that were of interest.
I added more trout and killed everything..
I initially blamed electrocution, from a failing circulation pump..

My lastest belief.. They died from cyanide poisoning..

Reasoning... there was same bright green powdery algae on on special raft bed

I wanted to add more trout, so I salted the water,. And later added more trout

The bright green algae turned dark. And all the fish died in serious distress..

I read... that the death of Blue-Green algae releases cyanide.. that death can be possibly temperature drop initiated and we also had a cold snap..

See the post by EarthBound in FISH PROBLEMS .. ESSENTIAL READING.

PS... thinking you MUST add more fish is not completely necessary .. you can supplement for a time, and other "animal" urine can work, provided no medicines are being used..

PPS .. do you have AIR in all the raft beds.. I am assured that air is needed everywhere.. otherwise, at night, the plants use oxygen and thus deplete it from the system.. night circulation will thus push depleted water to the FT.
..

30 to 40 goldfish and a few Lou is WAY overstocked for a 50 gallon tank. I only keep 30 to 40 goldfish in a 275 gallon tank to put it into perspective.

*koi - stupid auto correct

+1 WAY, WAY overstocked

Everyone -- thank you for the input. I was out all day and just checked the posting. I returned to a couple more dead fish, which is pretty discouraging. I will see about trying to insulate the tank to see if that helps with temperature fluctuations. I will also be certain to NOT replace the fish that died, since it is pretty clear that I am overstocked.

I will also check out EarthBound's post about fish problems.

Again, I appreciate the expert advice. While I know a lot more than I did just a few months ago, I am still definitely still a novice. Rather than trying to learn everything before starting (which I think is impossible), I just plunged in and am learning as I go. Hopefully, I don't kill too many fish.