Backyard Aquaponics
A place to discuss aquaponics

Howdy folks, its been a while since I've been on the forum. I forgot how much fun and informative it is. I took a new job and don't get the time to get on line for fun as much.
I have a good friend that makes 500 gal. cement septic tanks, code changed and he has some that are not usable for septic they have never been used for anything.How would these work for fish tanks? I thought about burying them partially because they are 6 feet deep. I also would like to hear any other ideas for uses.

Pictures would be great. Sounds promising.

The only thing about cement is that it will pull your pH up. Wash them down well with vinegar well before you use them

Or paint them with bichumin paint (which is used for potable water uses), and that will stop any leeching

yeah a 6 ft tall tank fully above ground wouldn't be as good as it would be if they were burried enough so you can see into the top....

I'll try to get by and snap some pictures. The concern that I had with burying them is I wanted to raise talpia in the warm months I was concerned that it might keep the tank to cool. Although we are down here in the south the sun will probably warm something that small pretty quick.

As a sanity check (oh wait, we're all insane here), you could check the temperatures of your local swimming pools. If you don't think they are warm enough, perhaps you could get black bichumin paint. that would warm the water very nicely.

in hardin you won't have problem with the coolness of the ground if you have enough growbed surface area in the sun to have solar heat transfer. Also if tilapia is the fish of choice, the ph will not be sa significant problem either as they enjoy higher ph levels and are a very forgiving fish. (they can be killed though!)

However, the high ph will affect the bacterial growth and some veggies don't like high phs (ie) tomatoes. Over time the ph will come down to levels that are tolerable for all parts of the system. IMHO I would not worry about painting. The vinegar rubdown would be a good idea to give you a lower starting point.

You need to bury the tank or your grow beds will be too high to be functional depending on your system layout. Take it from someone who has to use a stepladder to harvest his veggies. The best and simplest way is to get the tank as low as you can and be able to care for the grow beds with both feet on the ground.

But what do I know?

I do gain about 5 degrees F from solar gain on a nice summer day, and that's through insulated windows.

Yeah that shouldn't be an issue swimming pools in the summertime around hear warm up quite a bit, atleast to 80 deg. F.
I thought about leaving the tank out of the ground about 2ft. should that be good? Also would it be far fetched for me to believe that I could raise trout or some other fish in the winter. We have pretty mild winters most of the time we probably average above 50 deg. on occasion will have a cool snap for a few days and we may get below freezing at night .

I would sink the tank to whatever depth is comfortable for you, keeping in mind that the further out of the ground it is, the more the temperature will swing during 24 hours.

For trout, I would check on the expected time to grow out the fish to a decent size before it gets so hot they die. Also check whether you can actually get some trout locally, and what size(s) you can get. Mature trout are stocked here in local streams, but the expectation is that fishermen will catch them all in the Spring before really hot weather sets in. Our streams get too hot for the trout to survive through the summer. It would be really sad to have a bunch of 5 inch fingerlings with hot weather approaching too fast.

As a comparison, tilapia are very fast growing, and if you start with 1 inch fingerlings, and can feed them at a good rate, you can be eating your first ones in 6-7 months.

I though about using concrete too. Why not drop a pond liner or some 6 mil plastic from the hardware store?

Thank you Ma'am for you insight it is very helpful. I am pretty sure that trout are available in this area because the city stocks a load of them for the kids to catch in park pond each spring. Is there a strand of trout that are more tolerant of warm water?(maybe a good question for the troutman)

I would use the trout they stock locally. they will be easier to get, and most likely to tolerate your local conditions the best.