I know that several materials can leach plastics or other undesirables into the water. What material is the most non-reactive, durable, and affordable? I am looking to get something in the 250 gallon (925 L) ballpark. I don't want to have to go through the intensive cleaning processes that have been described concerning some of the tank options. I want a tank for the long haul with little maintenance and upkeep.
I've seen this option, which is a fiberglass tank from Australia.
Any thoughts on this design/material? Any feedback is greatly appreciated!
HDPE plastic is the most inert and generally a good choice for aquaculture tanks if you don't have the money for a beautiful figerglass tank and don't have the skills or know how to build one yourself.
IBCs are made of HDPE but you mention not wanting to mess with cleaning them, you might be able to find one new or already clean if you are willing to pay extra.
However, if you can find a rotomolding plastics manufacturing company in your area, you might be able to buy a nice round aquaculture tank from them. I know the place not too far from me will sell the "factory seconds" quite cheap, they are the ones that have some minor cosmetic problem but are still structurally sound.
If you go fiberglass you want to make sure it is either made with food grade resin or has a proper gel coat.
If you go with metal tanks they need to be lined to keep the galvanized coating from leaching zinc into the water which would harm fish.
If you go with plastic, polyethylene (either HDPE or LDPE) is generally the safest.
Liners are a huge subject. There are liners out there that have food grade ratings even though they are made with plasticizers that will leach into the water (flexible PVC or vinyl.) There are other liners out there that don't get the "food grade" rating but that have been used long term in aquaponics with no known issues (EPDM). then there is a PE liner durascrim that gets the food grade rating and it is nice and white, however it is not very flexible for folding into anything but rather simple rectangles (don't try to make an ornamental pond with it.)
Hope this helps some.
I don't believe the Rubbermaid or tuff tubs stock tanks have an NSF stamp for food or potable water grade. I know the rubbermaids are HDPE structural foam but they won't claim food grade though they must be feed grade at least and many people use them for aquaculture and I've even heard of people using them as birthing tubs. The Tuff Tubs, I think are LDPE, they use them as feed troughs and water troughs for animals but they don't claim them as food grade. So apparently they are good enough for feeding our food with but no one will say that they are "food grade" does that make them good enough, I guess you will have to make your own call.
There are companies out there who sell stock tanks and aquaculture tanks that are made with all FDA and USDA compliant materials.
Well, I've also found that it is hard to sell rubbermaid tanks when people can get them for the same price you can from Tractor supply. If you want to sell kits, you need to be able to bet the product for less than you intend to charge for it, in which case you need to find a manufacturer that will sell you the tanks for cheaper than the customers can get them retail. I've found that rubbermaid isn't really interested unless you are buying whole truck loads at a time.
The really challenging thing with tanks, is they are costly to ship since they are big and yet mostly air. It also tends to cost more to ship freight by common carrier to residential addresses. So, if you have a big truck, find a manufacturer close to home that already makes the type container you want.
The Poly tank I've had on the tower system seems good. I've not gotten several more poly tanks. The blue one seems to be holding up well. Of course now I'm putting my fish tanks in the new Fish shed so they won't be out in full sun all the time.
I've built some beds and I've used 100 gallon Rubbermaid Stock tanks as beds and both work.
As far as poly tanks as beds? Are you thinking of the mortar tubs? Those need an awful lot of support/reinforcement to keep them from bowing and cracking.
My tank is 440 gal, round fiberglass with gel coat. Con: expensive. Pros: vortex in the tank drives solids to the middle for pump pickup. Grow Bed drains enter fish tank at the top and pickup is at the bottom - that, in conjunction with the vortex gives a good mixing so there are no anaerobic zones or low O2 zones. I like it. The fish seem to like it, although I wonder if I have too much current in it at the moment - they're swimming a lot. They seem to be very healthy and feed like little Sumo Wrestlers. I'd say the positive attributes of my tank have more to do with it being round than with the fiberglass construction. Once you start shopping round tanks and shipping, there may not be a huge difference in price. Fiberglass is durable and repairable.