Trace elements, Water Change, Diana Walstad and random thou

[teejay]

hi all,

In Diana Walstad's book, she mentions there r only 40+ (if i remember correctly) elements used by all kinds of plants.

so, given that i add in all these elements (via pmdd) at the right level, there shouldnt be any need to change water. am i right? what r your thoughts?

[sherchoo]

Water change is still necesary to remove excess elements like NO3 which comes from fish waste (after bio filtration).

[juggler]

Actually 16 elements, not 40.
I found some info at http://members.aol.com/yamatoaquariu...rients101.html:

Macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S).

Micronutrients: boron (B), copper (Cu), Iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo), and zinc (Zn).

Non-mineral nutrients: hydrogen (H), oxygen (O), and carbon (C).

[bclee]

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On 4/21/2003 1:49:29 PM

hi all,

In Diana Walstad's book, she mentions there r only 40+ (if i remember correctly) elements used by all kinds of plants.

so, given that i add in all these elements (via pmdd) at the right level, there shouldnt be any need to change water. am i right? what r your thoughts?
----------------

Theoretically, yes.

Practically, no. Every plants has different requirements. Under different lighting conditions and CO2 level, the requiremens also differs. Fish load & fish food adds to the variables too, not to mention the nutrients "hidden" in the substrate.

If you do not change water, at certain point of time, you are going to run out of some components while others become excessive.

BC

[ZeRoC00l]

Erm... is it ok if i just add topup water???

I haven changed my water for 2mths?? just add a scope of water every 5-10 days depends on evapouration rate.

I got dose PMDD, and the small bottle of trace element...

Lazy to change water....

[james]

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On 4/21/2003 9:13:58 PM

Erm... is it ok if i just add topup water???

I haven changed my water for 2mths?? just add a scope of water every 5-10 days depends on evapouration rate.

I got dose PMDD, and the small bottle of trace element...

Lazy to change water....
----------------

Interesting. Could you share how is your tank doing now? The size of your tank and also your plants and fishes load.

I would think that if one has a small tank or perhaps relatively higher fish load, the need to change would be more frequent...ie, less water mass to dilute the fish/plant waste.

[ZeRoC00l]

Up to date, no water change for over 2 mth ===> lazy n no time cos exams are near.

Weekly topup with tapwater (no anti chlorine, etc)
weekly doses of PMDD, trace elements from Dr. M_????? (K2SO4,MgSO4,Fe, trace 4 drops)

Plants growth stay the same, trimming plants once abt 3 weeks.
CO2 injection as usualy 1bps(day), 1 bubble per 5sec(night)

Fish: 20 cardinal
1 pleco
2 SAE
1 chinese algae eater
5 swordfish
? yamatos
10 helequin

Lighting: 6 X 18W FL Philips 865 Daylight
Tank: 3ft

3" sand: base fert (1yr)
root monster
fert pellets from NTUC (placed near lotus roots)

Temp: 26-27

Plants: 90% filled
2 tiger lotus - visible growth
1 4-coloured lotus - visible growth
2 species of green stemmed plants(no idea what name)- fast growth
2 species of red stemmed plants - slow growth
Xmas moss
Hairgrass
Java fern
taiwan fern (not sure, same in Mr Fish Auqaristik main tank)
bits of riccia (trying to get rid)

All seems to be doing well.. [] Lucky?

[CK Yeo]

Ah, the age-old "water change" debate. I suppose we will keep seeing this topic popping up every now and then.

I can only say that it is contraversial.

My stand is: Theoratically it shouldn't be too much of a problem. But for everything that you know is there and can measure, there are maybe a hundred more that you can't and don't know about in the tank. I wouldn't want one of these unknowns to built up and start having detrimental effects on fish... If you think mass balance, I am always dumping stuff into the tank (fish food, fertilizers, medicine, etc), if only 16 elements are taken by plants, what happens to the other elements/chemicals that are not? Call me paranoid, but I think changing water is easier...

ck

[Plantbrain]

There are two basic methods that emerge.

The non CO2/Carbon enriched plant tanks are based on the low maintenace abused method.

It works and I have done 6 of these types of tanks over the years and it always amazes folks how nice they look.

Many folks want this type of tank in the beginning. But they have trouble with algae and wonder over into CO2, dosing and higher lights etc.

If they follow a few basic tenents, non CO2 is a great method. I've altered a few things, namely the substrate in DW's method. Mine is Flourite and deep(9-10cm) with about a 2-3 cm layer of peat and mulm from another tank.
This never "wears out" like soil can.

Water was not changed nor does the glass need wiping except once every 3 months or so. Sometimes longer. Top off for evaporation only.

Moderate fish load, I add more algae eaters, the plants grow slower but so does the algae. Therefore each herbivore does more work per unit time.

Moderate light, 0.4w to .5w liter is good.

You can try this same method with CO2 also for excelelent results but you will need to dose weekly and do the weekly water changes to maintain the levels and keep them from getting too high/low.

CO2 methods work better using water changes to maintain the nutrient levels.

The non CO2 plant tank is more balanced and the slower growing there fore the tank needs less NO3, K, PO4, traces etc. Root uptake can supply most of the nutrients and the fish food/waste will add the P/N etc.

I add some type of floating plant(10-25% surface area) and one plant that can use HCO3 as the carbon source.

The non CO2 tank is not for compulsive pruners, water testers, and other folks that cannot leave something alone. It requires more patience.

But the rewards are worth it.

It works for different reasons than Carbon enriched plant tanks but maybe not.

Regards,
Tom Barr