Backyard Aquaponics
A place to discuss aquaponics

I'm back to ask more dumb questions. I'll have to confess I have little experience with carpentry in general....

Anyone have any good tips on how to calculate the load a given structure you plan to build can handle? While I may be able to figure out how to put some of this stuff together, and even how I might make it stronger, at the end of the day, short of an actual test, I have no idea how to calculate what kind of a load something can actually handle.

I'm seriously considering constructing my own growbeds and tanks after reading more of the posts around here are looking at various systems. Among other things, building my own will insure I can get exactly the size I want and appears to be much cheaper at first glance.

I'm figuring pond liner, and wood for the bulk of the construction. I'm hoping to use masonry blocks (what I have always incorrectly referred to as cinder blocks) for the stands. I need to work out how far apart I can place my blocks, how to group them, if I'm fine just stacking them or if I need to throw in some cement for stability, how thick I need to go with my wood, and measures I need to take to insure the longevity of the wood and avoid warping in the long run through proper reinforcement up front, etc. I've always meant to get more into carpentry anyway, just something I've never had the time/opportunity to really mess with before.

Links are fine, I don't really expect anyone to walk me through this one step at a time. I think a lot of it I can puzzle out over time, just unsure how I might be able to go about load calculations.

Thanks,

Gene

do a detailed drawing, and I'll try to give you some suitable sizes.
Until I know size shape and growbed media type, I can't really comment. Send us your plans and we'll either tell you what to change, or how big to build it

The important things about using blocks as supports are;
1) place the blocks with the holes facing up and down.
2) you will need to make sure the blocks are placed level both to them selves and to each other. If there is a slope involved, you will need to dig down and create packed level pads for the blocks. If things are sloping, it will only tend to get worse till things fall over.

Well, the one important piece of information I don't yet have are the dimensions of the space I'll be working with. Here's what I do know:

1. I plan to do it all on a concrete pad.
2. I plan to have it all either level or with just the slightest of slopes for the growbeds. Haven't really decided yet whether a slight (and I do mean slight) incline for the growbeds would be beneficial or not.
3. I need roughly 200 sq ft worth the growbed space.
4. I want to be as space efficient as possible. I see this as being one of the motivators for building my own beds and tanks - I can get them the exact sizes I want them.
5. Having fooled with sq ft gardening some, I'm inclined to think the optimal growbed width is 4 ft. Feel free to comment if you think this is too wide. Also keep in mind I'm tall - around 6'3". The goal is to have the growbeds as wide as possible (walkspace wastes potential growspace) while still narrow enough that everything can be comfortably reached if you have access to both sides of the bed.
6. The more square the room is, the more optimal the space usage seems to be from my calculations. I see myself having a back wall (north) lined with tanks (I figure 2 at a minimum since I'd like to prevent any 1 failure from causing a total system failure), a front wall (south) lined with a sump tank (open to suggestions here if someone has a better idea), and rows of growbeds running front to back with growbeds up against the east and west walls as well (these might be less than 4 ft wide if that seems too wide to handle from one side). Walk space between beds probably needs to be around 2.5-3.0 feet wide - haven't quite worked that out yet.
7. I do intend for the beds to be somewhere between 12 to 14 inches deep.
8. Media type I'm planning on some sort of gravel since that seems to be what's affordable. It seems like a lot of different things pass for "gravel" these days though, so I've got to figure out what isn't pH dangerous. Also, I'd like to use shells to help buffer if I can find a decent source for them.
9. Fish type still hasn't been determined, but given the VERY strict laws where I live concerning raising fish, channel cats and brown/rainbow trout are good possibilities. I'd really like to try several different sorts, but short of a lot of money and legal paperwork, and if I'm lucky - exceptions, that probably won't be possible.
10. I intend for the whole thing to be in a greenhouse or possibly a very large sunroom (whichever ends up being easier to do). I do intend to heat it and run it year long.
11. In whatever space I have to work with under the growbeds, I'm hoping I can fit some bins for a fair amount of vermiculture. Worms seem easy enough to raise, and everything I've read tells me the fish will love them. Somehow my gut tells me the worms are going to be better for the fish than any commercial fish feed I manage to buy as well. I doubt I can raise enough to avoid needing to buy fish feed (where will I get that much stuff to feed the worms??) but the closer I come, the happier I'll be (still need to find a good way separate the worms out from the dirt). Leftovers from the worms (castings, tea, etc.) will go to build up the soil in my dirt garden outside for all the things to large too raise inside (mellons, squash, etc.)
12. I like cheap. I'll spend to make sure I get things right (paying for something twice because you went "cheap" the first time isn't cheap), but if I can save a few bucks here or there, I'd like to.
13. It also has to look nice enough my wife believes it increases (not decreases) our property value and our neighbors will believe I'm only half crazy instead of totally off my rocker (I've mentioned the possibility of soliciting our neighbors for garbage such as lawn clippings I may be able to feed to the worms...)
14. Plumbing is still being worked out. I do like the idea of draining from the tank to the beds, though it would be nice to eliminate the sump, but there seem to be a lot of good reasons to keep it. I'll pump from the sump to the tank. I have some ideas for possibly incorporating some RSG type filters between the beds and the sump. Still up in the air on that one.
15. Some sort of computerized monitoring would really be nice if I could find some probes that won't cost me a fortune I could hook up to a network and/or computer (I'm a network engineer with a programming background - I've got "geek" stamped all over me - ask my wife...). I haven't quite determined yet whether I want to trigger my pump based on timers, detectors of some sort, or the computer should I find enough cheap dongles of various types to make that feasible (and yes, I'm aware that involving a computer in the pump cycle just added a number of additional things that can fail - I'd probably have a backup system of some type to generate various alarms to get my attention if I went that route). Short of computerized monitoring, I'm going to need recommendations on good (yet hopefully cheap - more emphasis on good though) test kits for pH, DO, and the various macro and micro nutrients.

Hmmm, guess that's a lot more than bed dimensions. It's what's been on my mind though

All feedback/suggestions/info is appreciated.

Thanks!

- Gene

Sounds good. The concrete is unbeatable for stability for a foundation and I think maybe a quarter inch slope (per grow bed) helps make sure that things drain better, but level or even a quarter-inch backwards is fine as it never drains completely anyway: plumbing gets in the way.


I have to agree with you on #4. The plywood aquarium thread has some good ideas, especially cost effective it you leave out the viewing windows. I have one that measures 4'x19'x4'tall. Then again, the tank that TCLynx is just setting up on her thread is an inexpensive, strong, and effective way to make a tank.
Watch out on #5 as some plants really spill out across a walkway, it might take a bit of planning. Your idea of 30" to 36" sounds good.


I've never seen gravel that is actually unsafe, except some synthetic stuff one that was intended, I believe, as fertilizer filler. It may raise ph high, but not too badly and it will wane. You might try a blue small system just to try your carpentry, test ph effects of the gravel, etc. Later it would make a nice quarantine system. You can get shell grit from a feed store where it is sold as a chicken feed supplement.


How about an integrated sump tank? viewtopic.php?p=132602#p132602
So far nearly a year with 4mil visquine as a liner and no punctures. There are certainly some changes I would make, though...like double liner and an emergency sump overflow so it can not soak the bottom of the growbed.