# [Wet Thumb Forum]-metal plant weights and Ecology of Planted Aq.



## imported_Piscesgirl (Feb 19, 2004)

Diana -- I'm not much in the way of a scientist/mathmetician, but I skimmed the chapter about toxicity and I noticed that zinc can be toxic? What about those metal plant weights? (I think they are supposed to be zinc/nickle? -- azgardens says they are 'safe.') How do I know how much is too much? I haven't been using the plant weights for plants, but I have been using them to hold down zuchinni for my fish and shrimp.


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## imported_Piscesgirl (Feb 19, 2004)

Diana -- I'm not much in the way of a scientist/mathmetician, but I skimmed the chapter about toxicity and I noticed that zinc can be toxic? What about those metal plant weights? (I think they are supposed to be zinc/nickle? -- azgardens says they are 'safe.') How do I know how much is too much? I haven't been using the plant weights for plants, but I have been using them to hold down zuchinni for my fish and shrimp.


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## Roger Miller (Jun 19, 2004)

Speaking for myself, I would avoid using any metal in an aquarium -- particularly anything with copper, zinc, nickle or lead.

All of these metals are probably safe (relatively speaking) in short-term exposure if the pH is consistently alkaline, your water is naturally hard and you have some organics in the water to help complex the metals.

If your water is naturally soft, the pH is low and organics are missing then those metals can be poison. The toxicity level varies quite a bit from critter to critter. If you want a natural tank where you maintain a wide variety of life forms then you will probably come across something that is sensitive, especially if you consider eggs, larvae or fry.

if you parboil the zucchini or zap it in a microwave then it should sink without weights.


Roger Miller


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## hubbahubbahehe (Mar 29, 2004)

i have them in my tank holding down the riccia in my tank.... doesn't seem to be bothering them....perhaps the zinc weights are not leeching into the water?


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## imported_Piscesgirl (Feb 19, 2004)

Well, I'll be on the safe side and I won't use them anymore...but, I did zap the zuchinni in the microwave and it still didn't sink


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## Wally (Aug 31, 2003)

Why not just use on of those plastic clips with a suction cup on it?


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## imported_Piscesgirl (Feb 19, 2004)

Well, I have those, but I worry that the fish/shrimp will somehow push the zuchinni such that the clamp will close on them. I know it seems far fetched..but...


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## hubbahubbahehe (Mar 29, 2004)

what plastic clips?


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## Wally (Aug 31, 2003)

Here is a link as to what I am talking aboutveggie clip


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## dwalstad (Apr 14, 2006)

> Originally posted by Piscesgirl:
> What about those metal plant weights? (I think they are supposed to be zinc/nickle?QUOTE]
> 
> I always thought the weights were made of lead, which is even worse. In any case, I wouldn't put any kind of metal in my tank.
> ...


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## imported_Piscesgirl (Feb 19, 2004)

Well, everyone says that Zuchinni doesn't float if you microwave it, but maybe I'm microwaving it wrong? (can you microwave something wrong?). I microwave it in a bowl of water...maybe I should microwave it by itself). Mine floats


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## Roger Miller (Jun 19, 2004)

When I was feeding zucchini I blanched it instead of microwaving it. Low-tech I know but it works. I cut up the zucchini, put it into a pan of water and brought the pan to a boil. Once it was boiling I set the pan aside and let it cool off. Usually the zucchini would sink before it was cool enough to do anything with. I also made more than I needed and froze the extra.


Roger Miller


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## imported_Piscesgirl (Feb 19, 2004)

well...my cooking pans are all metal -- and teflon! I don't think that would be very good...


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## Roger Miller (Jun 19, 2004)

I think if metal cooking pans were a problem then we would all be at risk. Stainless steel, cast iron and aluminum are pretty safe. Teflon is very inert.


Roger Miller


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## imported_Sue (Jan 31, 2004)

Actually some cooking pans are a problem. There are links to alzheimers with aluminum pans and teflon is extremely toxic to birds when overheated.


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## imported_Piscesgirl (Feb 19, 2004)

Well, I microwaved the zuchinni a different way last night and it sank. Instead of using a bowl full of water, I put it in an empty bowl and covered with a wet paper towel. Somehow that made the difference!


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## Nillo (Jun 11, 2005)

I was using those weights for a while and then I discovered a better way to keep the fresh spinach down. There is a fabulous pproduct that I would have thought that Amano would have thought about since it comes from the bonsai trade. You can get anodized aluminum wire in a variety of gauges. I have some that is 2.5mm thick. The nice thing is that it is anodized brown to blend into the bonsai tree. Well I'm sure you can see how useful this would be in aquascaping. It bends very easily, but holds it shape well.

Anyway, here iis what I do to hold stuff down. If I don't need to hold a bunch together and just need to hold a rhizome down till it roots, I just cut a length and bend it in a "U". Here is the most important part, don't just stick the "U" in and think that it is going to stay well. Take the points of the "U" and bend them back on themselves to form a barb. This will keep the wire in place in the substrate. The variation for a bunch a spinach involves taking that "U" with barbs, and coiling the wire in the center around the bunch and then sticking the barbs in the substrate.

It is also fantastic for tying plants to inanimate objects.

I wish I had a online source for this stuff, but I live next to Little Tokyo in LA and there is a shop that carries it.


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## imported_Piscesgirl (Feb 19, 2004)

Is anodized aluminum non-toxic?


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## dwalstad (Apr 14, 2006)

Aluminum is not toxic at neutral pH. Soil is full of it. At acidic pH (around 5.5), it can become acidic and kill fish, etc.


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## hubbahubbahehe (Mar 29, 2004)

Ms. Walstad, what is the ph of your soil substrates?

I bought your book (great book, btw) and i noticed that you did a test with different types of soils. Very interesting stuff.


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## dwalstad (Apr 14, 2006)

The starting pH for my 50 gal's substrate was about 6.0. However, after liming it and submerging it, it probably became neutral or slightly alkaline.

The potting soils usually start out acidic because of the spaghnum moss (pH 5.5).

However, I can't answer your question, because I haven't measured the pH AFTER submergence, a difficult process. 

Soil pH changes as a function of simply being submerged under water. See the figure on page 130 of my book where the pH of one soil went from 3.5 to about 6.3 after about 6-8 weeks of being submerged. In general, the pH of all soils seems to go to neutral about 3 months following submergence.


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## hubbahubbahehe (Mar 29, 2004)

yea, i reread that section of your book. FAscinating stuff i gotta tell ya. It appears that even high ph's like 8 will eventually go to 7.... that means if stuff has carbonates in them, that eventually it will be gone and then will be fine right? so we don't have to do anymore muriatic acid tests...?


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## dwalstad (Apr 14, 2006)

I've never tested my aquarium substrates. I didn't know that people were doing this. Oh well!!


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## Nillo (Jun 11, 2005)

Would the acidic substrate continue to free aluminum ions into solution, or would the exposed ends oxidize and protect the aluminum from further degradation?


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## imported_timlawyer (Jul 14, 2003)

Nillo - Cool idea regarding the anodized aluminum wire....where can I find some?


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## Nillo (Jun 11, 2005)

You will probably find it at a bonsai supplier. I get mine in Little Tokyo here in LA.


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## Phil Edwards (Jan 22, 2004)

That's a great question Nillo! 

I'm not 100% sure about aquatic environments, but I would guess that constant exposure to an acidic environment would continually remove the Al from the source. That's what's happened all over the place with acid rain. The HNO3/H2SO4 leeches into the soil and causes the Aluminum to precipitate out of the soil where it gets bound up in trees, which blocks Mg uptake and kills the plant. 

Diana or Roger, can you confirm/deny this?

Best,
Phil


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## imported_Piscesgirl (Feb 19, 2004)

Umm...I think I'll pass on the aluminum wires then too....


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## Nillo (Jun 11, 2005)

But that would be from a soil borne source with huge surface area due to it's prevalence in the earth's crust. The other extreme difference would be the transitory nature of the clips. Also, weren't those lakes rediculously acidic? I just haven't experienced anything like that in any of my tanks, and I have been using the anodized aluminum wire for years. I think that if you are woried about aluminum poisoning of your plants in an acidic environment I would be more worried about the aluminum in the soil.

I don't mean to get too defensive, but they work fantastically.


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## Phil Edwards (Jan 22, 2004)

Nillo,

I've never used Aluminum in my tanks before and have no experience to back anything up. I was talking about the effect of acids in soil and the resulting kill off of plants. I wasn't at all trying to put your experience down, I'm sorry if it came across that way. 

It's likely that the amount of Magnesium added to your tank (If you do add Mg) is greater than the amount of Al going into solution. Furthermore, with the possibility of foliar uptake of nutrients your aquatic plants aren't going to be as effected by Al in your water. 

Thank you for letting us know that it's possible to use that type of wire rather than lead in our tanks. I'm getting tired of using highly visible plastic zip ties in my tanks.

Best,
Phil


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## Roger Miller (Jun 19, 2004)

As I said way back at the beginning of this thread, I try to avoid using metals in my tanks. Aluminum is generally not a problem. Aluminum reacts with water and that reaction creates a skin of aluminum hydroxide on the surface of the metal. The coating prevents further reaction and the metal is safe and stable. If the pH of the water is too low then the protective skin breaks down or doesn't form and aluminum ions can be released into the water. If the water is also very fresh then there is nothing to form complexes with the aluminum ions. Then the aluminum may be toxic.

Low pH, in this context probably means values well below 6.5. The pH in a peat substrate can be low enough to cause problems, so don't bury aluminum (or any other metal) in a peat substrate.

The aluminum that causes problems in soils effected by acid rain comes from minerals in the soil, most of which contain large amounts of aluminum. At low pH the minerals break down and release aluminum.

The pH of clay soils in the SE US is sometimes low enough that crop production can be limited by aluminum toxicity even without acid rain. That little bit was on the Clemson ag. extension web site a few years ago.


Roger Miller


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## Chapy (May 3, 2004)

Hey all'
Going back to the metal plant weights,
I am curently using one to hold down my moneywart. It doesn't have any roots right 
now but in the future I will not use it.

The other suggestion I have for you is; go to walmart or any store for that matter and get those small 1" clay pots and start you plants off that way. I have one like that now and it adds alittle somthing to the tank. I just add some soil put the plant in and add gravel. Then I drop it in were I want it.
Well thanks for listening. good luck all I enjoy learning from you.
Chapy


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