Backyard Aquaponics
A place to discuss aquaponics

Has anyone here tried building tanks with loose cinder blocks like this?

http://www.monsterfishkeepers.com/forums/showthread.php?t=147414

I like the idea that the whole setup can be ripped down. I noticed that he says this is 30" but I think it's only 24" deep (it looks like 3 layers of 8 x 8 x 16 cinder blocks).

How would you plumb something like this with a SLO?

Seems like a really quick and easy way to setup a large tank. Where I am the blocks are $1.28, I'm sure the wood would cost more.

Any thoughts?

No reason it would not work. For a SLO or other overflow you would just need to plumb through the pond liner. There are various bulk heads available for that and silicons for people like me that don't plan properly and have to plug leaks. Looks like he built his on a patio. It would be pretty important to have a nice flat surface to build on and in a place that would not be bumped by mower, vehicle or anything that might be able to move the blocks.

Should work okay. They have some nice tanks on that site.

Hi Scotty:
From what I remember Travis Hughey's outside pond is done using dry-stacked blocks. As long as you don't try to make it too high it seems to be an OK thing to do. Might want to guard against someone walking on the edge of it and knocking the thing down maybe.

Here are the two options I am considering

1. Cinder block tank with a wood top layer sandwich and top to trap the cinderblocks but also extend the liner up and to allow a SLO overflow through the wood and liner. Also wood bracing around sides.

2. Behlen stock tank surrounded with cedar or some other covering to meet with the approval inspection. My wife thinks she's the only one with a tub in the backyard, sheesh!

I'd kind of like this to be like a pond but only plan on around 420 gallons of growbeds at this time. I was thinking 500 to 1000 gallon tank with low stocking levels to compensate for the lack of growbeds. Probably would burry the tank half way into the ground. It rarely gets into the 20's here but when it does it's likely to be for a week or two.

If you guys had the choice would you go with a cinder block and liner type pond or a behlen stock tank and why? The cinder block tank could be made to fit the space where I would have to shift the behlen tank further away from the growbeds but it might be more durable.

I don't know if you have them in the states but I'm currently researching retaining wall block tanks (among other tank designs) and a stylr of block called versaloc that kp put me on to. The retaining wall blocks and the besser block wall s if fine gravel filled are good for three courses, higher than that (or deeper depending on your point view) you would fill with concrete and reo. For a liner we are looking at a spray on liner which will give a very good finnish but is expensive (~$20/m^2).

I was thinking blocks for my system and grow beds too
I was thinking to make it permanent and cementing them in core filling and rendering them so they look good and are water proofed without a liner.

Grow beds I was visualising making a table out of blocks with a thick cement sheet floor(table top)
then building a block wall on the table as the growbeds.

anyone ever done this and if not is it un possible

Blocks are about $3-4 delivered plus concrete and reo and rubber paint

will do the maths (when I am ready) but I imagine it will be comparable to plastic if not cheaper and look better.

I want the liner for the FT to get rid of the rough concrete sides so that the fish are not injured by them. For the GBs a liner (LDPE) over some sort of structural support is cheaper than the concrete fill.

Never thought about rough surface but it would be a factor for infections.

Sort of surprised that held together, especially since he did not stagger the blocks so they overlapped. Guess the wood is the only thing stopping the blocks from slowly sliding out or tipping.
I am certain any surge of water, ie kids falling in, dog belly flopping into it would see a flood.

Regards rendering you need to consider sealing it otherwise Ph rise from the lime will be a long term issue.

Definitely would go with a liner in the fish tank so no actual contact with the concrete. For building the beds unless they are out in the rain I probably would go with wood, then a liner, like these - http://picasaweb.google.com/aprovecho.mail/Aquaculture2010#

They lined both the top and the bottom portions so you have a sump right below the bed. I think this groups focus is a little different since they filled the beds with aquatic plants - so they are really more interested in filtering water for their fish than growing veggies at this point. They could be doing DWC or fill with media and do flood and drain, hard to understand why they didn't.

The ones JT built would be another really good option - again these have the sump underneath but these use a lumber and plywood sandwich -
http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=5259&st=0&sk=t&sd=a&start=180

If you are seriously considering cementing the blocks and rendering it smooth, take a look at just pouring concrete. It is a lot less work, stronger, and can be cheaper. If done right, it will last longer then you want it to. I'll be starting a system thread here soon that will document my concrete system. They were supposed to start today, but a rainy day delayed it.

Concrete is one of the other options that we are considering.
However, the costings that we have so far put concrete at more than twice the cost of the masonry block tank. Ive got someone else doing me a quote for a concrete tank but he seems pretty busy and I'm not sure when he'll be getting back to me.

Wood with a liner is the cheapest in terms of materials but I havnt been able to cost the labour to my satisfaction. I have a builder friend who was advocating concrete very strongly and was very negative about the block construction. However, he was invisiging besser blocks were as the versalocs are more like a sacrificial form work. My friend now thinks that they may be the way to go.

Price though is not the only consideration. Something I learnt from my initial systems is that even if a cheaper tank works the time and energy spent worrying about whether it is leaking or not is not worth the saving.

The thing that gets me about concrete tanks is that the material for the form work is about double the material for a wooden tank and the labor in setting up the form work must be at least equal to the labour in building a wooden tank. Unless you are building multiple tanks so that you can reuse the form work it would seem that a wooden tank w will on price. However the concrete tank will be more durable and there fore might be the better option in the long run.

I've seen where cracking is an issue with concrete tanks in some climates. Probably is for cinder blocks as well.