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Chesh 07-07-2012 08:35 AM

How long are ferts active?
 
How long do the fertilizers that we add to the water remain active?

Do they stay in the water column until the plants absorb them or they are removed by water changes/tap conditioner? Or do they dissipate after a period of time? I suppose this may depend on the individual nutrients themselves. . .

Just curiosity on my part, but I've been wondering about this for a while!

An example of where this information would come in handy is if there were a tank with no fish and only ONE small live plant. If you didn't do water changes or de-chlorinate, could a single dose of ferts feed this little guy for a month? Or would you still have to dose every week because the nutrients become inactive or evaporate?


Thanks in advance for any input!

This has been your random question of the day! ;-)

equatics 07-07-2012 09:11 AM

Quote:

Originally Posted by Chesherca (Post 1144821)
How long do the fertilizers that we add to the water remain active?

Do they stay in the water column until the plants absorb them or they are removed by water changes/tap conditioner? Or do they dissipate after a period of time? I suppose this may depend on the individual nutrients themselves. . .

Just curiosity on my part, but I've been wondering about this for a while!

An example of where this information would come in handy is if there were a tank with no fish and only ONE small live plant. If you didn't do water changes or de-chlorinate, could a single dose of ferts feed this little guy for a month? Or would you still have to dose every week because the nutrients become inactive or evaporate?


Thanks in advance for any input!

This has been your random question of the day! ;-)

I don't think that fertilizers become inactive or or dissipate. For example, I assume that in most cases the reason nitrate is found in ponds and lakess and groundwater is runoff from fertilizing people's lawns. It stays in the rainwater and then in the groundwater.

However, to get back to your hypothetical tank, these days the illuminati are saying 20% (or more if necessary) weekly, and that does dilute the fertilizers. It is recommended to people who fertilize to do a major water change to "reset" the level of fertilizer before you dose again.

Oh, I meant to say that I think fertilizers work for algae too, perhaps if there is deficiency of one of the elements of the fertilizers. Others can explain this better and more fully.

Btw, I think that a single plant would have a harder time than a tank full of plants.

Glad to offer what little I know on the subject. Hope it helps in some way.

Steven

Byron 07-07-2012 10:58 AM

I have not had reason to look into the issue of how long nutrients remain in water to which they have been added as fertilizers, so that I cannot say. But I do know that if they are not present in the source water (tap water, well water) that is used for water changes, then they will be removed/diluted with each water change if they are not in the interim used by the plants.

Some plants can store some nutrients, this varies with plant species and nutrients. The number of plants obviously impact how fast the nutrients--totally or individually--get taken up. I have experimented a bit over the past few years and I know that in my tanks if I do not dose Flourish Comprehensive every week, by the week following the week I do not use it, the plants are showing signs of nutrient deficiency. So adding Flourish weekly is obviously needed in my situation. But I have basically no minerals or nutrients in my source water.

With respect to water conditioners, those that detoxify heavy metals will negate the "heavy metal" nutrients, which are copper, iron, manganese, zinc, nickel. These are essential for plant growth (photosynthesis). I have a 20g tank that i use to quarantine new fish for a couple weeks, and it is planted. I do a partial water change weekly, but when it is without fish i do not use a conditioner, since there is no reason. Chlorine is also a plant nutrient, and without fish there is no need to remove it and waste the conditioner, and it dissipates out of the water in 24 hours anyway. Most conditioners have a limited effectiveness, probably 24-36 hours, and after this they no longer do anything. I dose Flourish Comprehensive (which contains the micro-nutrients that are "heavy metals") the day following a water change where I have used a conditioner. I've no idea just how much the conditioner might mess with the minerals, but Seachem did caution me not to use the two together for this very reason, so...I don't mind waiting a day if it means not wasting money or depriving the plants.

Byron.

Chesh 07-07-2012 11:10 AM

Thanks! Looks like this one might have to remain a mystery :) It doesn't really matter - it honestly is just idle speculation and curiosity on my part.

Byron, your tanks are pretty heavily planted, more so than mine, and if you're seeing signs of deficiency after a week, then we can safely assume that in your tanks, the nutrients are all being taken up within a week or so. Question for you - do you only dose once a week?

I've been considering going up to 2x a week dosing, but I'm not really sure that it's necessary. . . there are many that are dosing 2x or even 3x weekly. . . how do you know when (or if) you have a need to up your dosage to more than once weekly? Aside from the possibility of algae, as long as the levels of ferts are kept low enough not to harm the creatures, I suppose overdosing slightly is okay, as long as weekly water-changes are done to 'reset' the levels in the tank, as Steven said.

I know that some plants, like floating plants, will take up nutrients more quickly than others. . . and others, like the banana plant, can store nutrients until they are needed.

It's all very interesting to me . . . thanks for the input, guys!

Olympia 07-07-2012 11:16 AM

I don't know if the chlorine gas used in water is used by plants, seems kinda weird.
And heavy metals are only made safe for a day?! D:

Chesh 07-07-2012 11:22 AM

I dunno about the chlorine, but if Byron says it's true, I believe it 100%!

As for heavy metals, I think the water conditioners REMOVE them from the water, so they aren't in there anymore at all. The problem is that the plants NEED them (in very small amounts that are also safe for the fishies) to survive, so you have to put them back into the water for the plants to 'eat' AFTER the water conditioner is no longer present in the tank to undo your work, lol. It's so convoluted! :roll:

Olympia 07-07-2012 11:24 AM

I just don't get how they can be removed. They'll still be in the water. Nothing is going to knock a proton out of iron to turn it into manganese. In essence the metal will always be there. It will just be converted to a different compound, perhaps one that is inert to the circumstance?

Chesh 07-07-2012 11:29 AM

Great question, Limpi! Now I'm curiousER!

equatics 07-07-2012 11:56 AM

Quote:

Originally Posted by Olympia (Post 1144960)
I just don't get how they can be removed. They'll still be in the water. Nothing is going to knock a proton out of iron to turn it into manganese. In essence the metal will always be there. It will just be converted to a different compound, perhaps one that is inert to the circumstance?

I agree with you Olympia. Perhaps it is because there are two kinds of heavy metals (unknown territory here) where one is available for assimilation and the other is not. It would be good if water conditioners converted the unavailable heavy metals into available ones. I don't know what the exact case is.


Steven

Byron 07-07-2012 12:01 PM

As I said, I have no evidence either way. I just went with what Seachem told me when I asked this specific question, and waiting one day is not hurting things just to be certain. But there is one possible explanation.

I would assume that conditioners detoxify metals by binding them somehow, and this will make them unavailable, and likely they do not "unbind" subsequently. This was the point behind Seachem's response. For example, one reason we do not want excess oxygen in a planted tank is because some minerals bind to oxygen, and the plants cannot take them up. Other minerals can bind to DOC (dissolved organic carbons); iron is known to bind in certain forms, and so forth.

As for how often to fertilize, this depends upon the plants and the availability of nutrients from the source water (water changes) and fish foods, organics decomposition, etc., and there are no absolutes because every aquarium is biologically different. I started out fertilizing once a week, then went to twice. After a while, I wondered if twice was necessary, so I cut back to once. I did notice a slight change after a couple weeks either way. But my main concern is carbon, as CO2, which is not being added by any means. Increasing the other nutrients beyond the carbon available is useless, and with the light will only contribute to algae. For several months now I have been doing once weekly dosage of Flourish Comp. I have substrate tabs next to the larger swords in two tanks (these do make a difference), and Flourite substrate in another though this has been next to useless. I also use Equilibrium to provide sufficient calcium, magnesium and potassium.


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