Tardy discussion on tank size/depth in Texas.

[txdurk]

To TCL et al: Ioriginally messaged everyone due to my unfamiliarity with the web page interface. Won't be the last mistake I make I'm sure. Hope I did it correctly this time.

Originally I had asked about tank depth since I could only find 2' tall tanks locally. i am less concerned about this now but TCLynx tells me not to use galvanized tanks; I presume due to residue from the metal cladding process or rust but I'm guessing here. I am actually more concerned with blue poly not being food grade but, maybe, I'm all wet. Thoughts?

[TCLynx]

Hay no Problem.  The Ning network has quite a few quirks we all get lots in occasionally.

I personally like deeper tanks than 2' but I like to grow big fish and fish also jump so some freeboard above the water line is a good thing.  But that said, many people use the plastic stock tanks as fish tanks and do ok.

Why not use galvanized tanks.  Well because that galvanized coating will leach zinc into the water which can reach toxic levels for fish and even for us and if you want to grow red claws or craw fish or shrimp, they would be especially affected by the zinc toxicity.  Now there are some galvanized tanks out there with an additional lining on the inside to make them safe as fish tanks or grow beds but the plain old galvanized stock tanks normally sold around the US are not aquaponic safe.

As to blue poly being food grade.  Well I don't expect you will find any food grade stickers on them but most stock tanks for feeding animals are not going to have things that would kill fish leaching out of them.  In general polyethylene plastic and even the structural HDPE foam they make the Rubbermaid stock tanks out of are safe for aquaponics.  You will have to make your own call about how "food grade" you personally need everything to be.  (And heck there are plenty of things here in the US that are "food grade" or "potable water safe" that still leach things that most of us don't want in our food.

Of the plastics out there, polyethylene and HDPE are among the safer choices as they usually don't use a lot of the plasticizers that make some of the other plastics undesirable.  Be more wary of the flexible vinyl or flexible PVC since it is the plasticizers used to make vinyl stay flexible and survive in the sun that tend to leach out.

[txdurk]

Thanks for the education TCLynx.

[txdurk]

I found some poly tanks of a good depth (child proofing is required) but they are expensive especially with shipping: http://www.pondsolutions.com/holding-tanks.htm

[Chi Ma]

Here are some good ones that are commonly used.

http://www.tractorsupply.com/rubbermaid-reg-structural-foam-stock-t...

[txdurk]

Thanks Chi Ma. I've gone full circle in my thinking/planning and had decided independently that the best tank for me to begin with is the 300gallon that is in your link. Great minds think alike.

i am also considering using the 50gallon vrrsion as growbeds - two in tandem per table making one bed total, if that makes sense. The 50gallon tanks are reasonably priced and all I need do is build a platform for each pair. I also figure I can add one or two more of these double beds using an indexing valve if I wish to expand the system. My worry with that layout is if the first double bed cleansed the water so much that the second and third beds would be deprived of nutrients. I have no idea if this should be a concern to me or not.

[Chi Ma]

Just add more fish:)

[George]

I'm using a 4 feet tall, round fiberglass tank and 3 1/2 or so of it is in the ground.  Don't know if such tanks are readily available in Texas but they might be.  They're expensive.

[txdurk]

Thanks George. My thinking on this has matured like anything one learns from scratch. My new criteris are:
1. Repurpose what I have on hand in order to save money; buy only what is needed.
2. Make it simple;
3. Make it easy to tend;
4. Don't fight the fish and game laws; stay away from anything that needs a permit.
5. Provide for my family of four with as little extra that is not consumed as possible; and
6. keep it sustainable.

To this end I have decided to:
reuse a 10'x20' dog kennel resized for 20'x20' to keep critters and kids out;
build my own grow beds;
stick with aquatic species native to Texas
down size my fishtank to something more manageable (i.e. 300 gallon tank) to support just enough to feed one dinner per week (fresh or frozen) to my family
of four;
produce enough veggies to supplement our table; and
use heirloom, open pollinated, seeds in order to plant every year from the previous harvest.

This is way more manageable and fits in nicely with my quail and rabbit meat production.

[Chi Ma]

I found out late in the game that somethings are better off being bought than DIY. lol. My time is way too precious. I could be doing something better like...fartin around :)

[txdurk]

ChiMa: I've tried to weigh that build-buy equation. Since I am retired now I have more time than money. Thst being said, I'm a disabled Cold War veteran and the VA took my drivers license until 1 May. So, I may be overly optimistic to my capabilities. As a compromise I have been thinking of building platforms only and using two 50 gallon Rubbermaid tanks side by side as one complete grow bed and have 2 or 3 of these double beds with an index valve.

Cheers.

[TCLynx]

txdurk,

    I will caution that wood and liner beds can be a bad idea in termite territory.  and if you want to save money on the platforms, you could just use 100 gallon rubbermaid stock tanks just on some blocks since they are taller you don't need to lift them up very high.  The 100 gallon tanks are usually only a few dollars more than the 50 gallon tanks and you get twice as much filtration and don't have to build a platform.

[txdurk]

TCL: Thanks. All good points.

I thought about termites so I would not place the 4z4 lega directly on the ground and instead place them on above ground deck footers and any termite tubes woould be easiky seen and the problem fixed with termite treatment. I was also looking at coated metal framing with wood decking. The frame would rust over time but would still provide a useful life. the other con is cost.

I see you use the 100 gallon tanks for beds. I don't like them because of the amount of media required to fill them and the cost but I'll do a cost/sq ft comparison with the other configuration before I finally decide. It might be cost effective.

Cheers.