Backyard Aquaponics
A place to discuss aquaponics

Thanks Tamo

Will give the normal cornflour a try

i've still got questions about the residue from rhubarb before i'll use it in my system.
does it break down or does it build up in the system?
the reason i'm scared is the active ingredient in rhubarb makes you form kidney stones, and passing one of them is like giving birth.

No, it is worse

your not the first person to tell me that either.
i guess that's the real danger of recirculated systems. the only outputs go into your body

was the active ingredient an oxalate? if so then it is destroyed by cooking. will look areound more and possible re-read this thread

yeh, it was. two points to consider.

Dont know where i got the "heat destroyes it" bit, must be thinking of another plant chem.......

here are some tidbits, those prefixed with an * are my own thoughts, others cut from wiki.

Even a small dose of calcium oxalate is enough to cause intense sensations of burning in the mouth and throat, swelling, and choking. In larger doses, however, calcium oxalate causes severe digestive upset, breathing difficulties and — if enough is consumed — convulsions, coma and death. Recovery from severe oxalate poisoning is possible, but permanent liver and kidney damage may have occurred.

*calcium oxalate is what makes up kidney stones, but oxalic acid is probably the cause of them, happily combining with calcium from the body.*

*keep in mind that calcium oxalate is insoluble, so any oxalic acid that enters the fish water would probably combine with calcium present in the water and precipitate out. as a solid its not going to be an issue in the growbed.*

The affinity of divalent metal ions is sometimes reflected in their tendency to form insoluble precipitates. Thus in the body, oxalic acid also combines with metals ions such as Ca2+, Fe2+, and Mg2+ to deposit crystals of the corresponding oxalates, which irritate the gut and kidneys. Because it binds vital nutrients such as calcium, long-term consumption of foods high in oxalic acid can be problematic. Healthy individuals can safely consume such foods in moderation, but those with kidney disorders, gout, rheumatoid arthritis, or certain forms of chronic vulvar pain (vulvodynia) are typically advised to avoid foods high in oxalic acid or oxalates. Conversely, calcium supplements taken along with foods high in oxalic acid can cause calcium oxalate to precipitate out in the gut and drastically reduce the levels of oxalate absorbed by the body (by 97% in some cases.)[7][8] The calcium oxalate precipitate (better known as kidney stones) obstruct the kidney tubules.

Oxalic acid and oxalates are abundantly present in many plants, most notably fat hen (lamb's quarters), sour grass, and sorrel (including Oxalis). The root and/or leaves of rhubarb and buckwheat are listed being high in oxalic acid.[6]

Other edible plants that contain significant concentrations of oxalic acid include—in decreasing order—star fruit (carambola), black pepper, parsley, poppy seed, amaranth, spinach, chard, beets, cocoa, chocolate, most nuts, most berries, and beans.

The gritty “mouth feel” one experiences when drinking milk with a rhubarb dessert is caused by precipitation of calcium oxalate. Thus even dilute amounts of oxalic acid can readily "crack" the casein found in various dairy products.

Common sense has long held that consumption of too much calcium could promote the development of calcium kidney stones. However, current evidence suggests that the consumption of low-calcium diets is actually associated with a higher overall risk for the development of kidney stones.[3] This is perhaps related to the role of calcium in binding ingested oxalate in the gastrointestinal tract. As the amount of calcium intake decreases, the amount of oxalate available for absorption into the bloodstream increases; this oxalate is then excreted in greater amounts into the urine by the kidneys. In the urine, oxalate is a very strong promoter of calcium oxalate precipitation, about 15 times stronger than calcium.

Oxalic acid can also be produced by the metabolism of ethylene glycol ("antifreeze"), glyoxylic acid or ascorbic acid (vitamin C). Under certain conditions of concentration and pH, oxalic acid can precipitate in the kidneys as calcium oxalate crystals, forming an estimated 80% of kidney stones.[9]

that's the one. could point about it presipitating out in the water. i wonder how long it lasts on the plant before breaking down? i know it protected my tomatoes from horn catapillar for a month, so i think if you use it you had better wash your food before eating.
it's also worth noting it didn't take a very strong batch to kill off the grubs. i boiled 4 leaves in 1 cup of water for 15 minutes, then sprayed it on.

Im not from the USA but a quick google returned these descriptions of Grits.

http://www.google.com.au/search?hl=en&s ... n&ct=title

Wow, look what happens when I turn my back on a thread for a day.

Steve good info on the oxalic acid. Sounds like more reason to drink milk. If only I could figure how to grow my own milk on a suburban lot! AP cows again?

I wish putting growbed stand feet in containers would work against the ants but not in my set up. My worm bins have their feet in containers of mineral oil that that has worked a treat to keep ants out.

I've tried grits against ants before. One time it seemed to work sort of but other times it didn't.

The boric acid powder seems to work if they are attracted by what you use for bait but I don't think I want that around my system.

Diatomaecous earth is supposed to work well against ants but I do know that the dust is very bad to breath so I'm not sure how to effectively or safely use such around the system. Would it be bad for the fish if it were to get washed into the system?

Standard Southern Grits are usually corn grits I think but it can be any grain ground to a grit consistency.

Thanks
Just get confused by the terminology ie corn/wheat/maize. Used to think grits were some belly pork dish

Some interesting bits on this Texan site http://www.nopesticides.org/alternative ... ials.shtml

Just goes to show you are used to what you are used to. I can't imagine not knowing what grits are

timmy, always prudent to wash (as in rise) your veggies any way.

have seen many an errant pigeon crap around the GB.

TCL, dont get me started on the milk thing i propose that we should all drink calcium oxalate because its high in calcium..............

I wonder if you went to countries where two glasses of milk and a slab of cheese were not daily houndings, if you'd find the bone density or osteoporosis rates any lower................

i get especially suspicious when the dairy associations fund the ads

sorry to any dairy farmers.

yeah but i'd be giving them a bit more of a wash if oxalate doesn't break down with sun exposure.
fyi bone density is highly dependant on impact exercise, something lots of people don't get enough of.

timmy, meant to write lower not higher regarding bone density.

re oxalate: calcium oxalate should wash off the leaves as a solid, and i dont think it would take much to wash off the water soluble acid either. and besides as you've said, you used 4 leaves............