Backyard Aquaponics
A place to discuss aquaponics

LMAO, I mean money wise.

Had a bunch of tilapia die over the last couple weeks. A few a day, not sure what is going on. Almost all of my tilapia in one tank are now dead. Only about 3-4 surviving right now. I isolated the fish salted to 10ppt for a day. Then did a water change and salted new water to 3 ppt and will leave it at that. Now the weird part, I have 3 tanks, one tank is attached to it's own system and the fish are doing great. The 2 other tanks are attached to the same system most where in a 1550 gallon poly tank, and 8 of my biggest ones are in a IBC tank. All these fish share the same water, and grow beds. The 8 fish in the IBC tank are doing great and eating well. The fish in the 1550 gallon tank are the only ones dying. I have no idea what is going on, my water tests seem fine, there is no metal in my tank, except what is inside of the pumps. I am using 300 feet of poly tubing as a solar heater, but also both tanks share this water. The tank water is crystal clear, no suspended solids, aeration is fine in both tanks. This is not the first time I had fish die in this particular tank, I am at my wits end with this. Other than digging up the tank and replacing it I am about out of ideas. Any thoughts are appreciated.

Here is the tank, it is made of Polyethylene

http://www.tractorsupply.com/storage-ta ... a--2125652

that's a pretty deep tank.. is there a "thermocline"? can you take the temp from the bottom of the 1500 gallon tank?
i'd think that a turnover of the water would affect both tanks though.. how deep is the tank buried?
are you pumping air down to the bottom of the big tank?

thermocline?

I can try to hold a thermometer at the bottom of the tank, but at worse it should not be less than 60F. I have 3 pumps running in the tank, one 2000gph that supplies all the grow beds, and the excess just circulates in the tank, 2nd pump supplies my duckweed tank, and solar heater, and circulates tank also. Third pump is about 2 foot from the bottom and all it does it send the water to the bottom and makes it spin in the tank. All my pumps suck off the bottom of the tank, so water turn over down there should be over 2500 gallons per hour.

Tank is about 6 foot below the bottom of my green house, which is about 12 feet below normal ground level.

Yes I am pumping lots of air to the bottom of the tank. I have a pondmaster AP-100, and it is designed for a 10k gallon pond. I actually have to bleed off air or the water is just to violent. It is supplying 5 tanks, my big tank (the one I have the problem in) the IBC tank, the duckweed tank, my poly tank which is the separate system, and a above ground pool outside my greenhouse with duckweed in it.

Thanks

Floating thermometer is reading 70F and the one I held at the bottom read 72F

This time of year for tilapia I would think of temps first. I don't think they'd be very strong health-wise below 70. Hmm, too much water for temp swings and 72 should be fine so ?

I have a small stock tank (900 gallons above ground) that the water is always colder than my big tank (it has gotten down to 45F, and not one fish had died in that tank. Lost about 265 total in the big tank. 70F is 21C

Thanks

There is a total of about 1900 gallons/7000liters in the system, not counting what is flowing through the grow beds. And now that I have the greenhouse temps have been very stable. Since I put up the greenhouse I have not seen the temp lower than 68 nor higher than 74f, and we have had some nights get down to low 30f near 0 C.

Are the fish doing anything unusual if you watch them for awhile - chasing each other, or anything like that? I had ones that would harass the other fish I think due to mating behavior, having less fish in a tank makes that worse supposedly, when there is a lot of fish together they don't do it as much.

BTW it's the tank, you should ship it to me to fix the problem.

LMAO, shipping would probably cost more than the tank. I am hoping it is something other than the tank.

As far as the fish behavior, nothing they just swim around the bottom of the tank. Rarely ever do I see them come to the top.

I have 24 (about 4 inches long) in a 55 gallon tank in the house and they are doing great. Took 2 out yesterday and put them in a tank by themselves because there mouths are full of eggs. I had 270 about 4" long in the big tank, but only have 4-5 now.

Did you ever figure out why the other fish deaths happened in the other system, was that about a year ago? Maybe farms nearby spraying pesticides or something like that. I don't think it's the tank BTW, that tank is nice.

My tilapia handle lower 60s just fine. They don't eat much, but they are ok. Are your test kits still fresh? As someone who sells fish finders, thermocline is a word I use regularly.

No, it just stopped. There are no farms near me, in fact no neighbors for over 3 miles. Nearest farm would probably be 10-15 miles away. Nothing around me but pine tree plantations.

Thanks, I sure hope it isn't the tank, but I need to figure out why they do fine for a while then all of a sudden start dying. This is my 3rd time having fish die.

The test kit is a API and is less than a year old, and the other tank of fish are doing great and they share the same water. Water is pumped from my 1550 gallon tank, to the grow beds, the grow beds then drain into the IBC (which is the one the fish are doing great in) and then the IBC is drains into the big fish tank by a SLO drain.

I notice with the tank it states STORAGE TANK and does not state it is for water for human use. I would check with the store and manufacturer in case it has been lined with something or recycled plastic has been used. Always better to be safe anf recheck the facts.

Many people use Poly water tanks as fish tanks with no problems. My own tank is poly and will be receiving the first fish on Friday. Hope it is nothing to do with the tank as it is a good size and well suited to your system.