Plant fertilizer efficacy duration

Avel1896

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Hello :)
How long does it take for a liquid fertilizer to become ineffective once diluted in aquarium water ? 1 week ? 2 weeks ? More ?
I guess EDTA is an important point ?
 

Byron

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I've never read of aquarium plant fertilizers becoming ineffective, but others may know. When added to the tank water, the plants take up what they require (provided the light is adequate intensity and spectrum to drive photosynthesis). Some plants can store excess amounts of certain nutrients, other plants cannot. An excess of some nutrients can also cause plants to "shut down" the uptake of certain other nutrients. Plant additives should always be minimal, because they do impact fish. I would also expect algae issues with excess fertilizer that is beyond what the plants in the tank require in proportion to the light.
 
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Avel1896

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So, addingfert once a month should be enought ?
 

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So, addingfert once a month should be enought ?

It depends upon the plant species, fish load, GH, etc. Each species of plant has somewhat varying levels, for example, Java Fern and Moss are very slow growing and thus need less intense light and fewer nutrients, than fast growing floating plants.

Given that the regular weekly water change would tend to remove nutrients, perhaps, weekly addition of the fertilizer would seem advisable if it is needed. Also, substrate tabs can really benefit plants like swords, aponogeton, etc, and these are safer than adding liquid to the water.
 
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Avel1896

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I already use JBL substrate tabs (small balls) that last 12 months, and EasyLife root sticks I place between bulb/rhizome/rosette and roots in case of of Anubias, Microsorum, Cryptocoryne and so on.
 

Colin_T

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Plants need a slow steady supply of food (plant fertiliser). If you don't give them any for a while they starve and when you do eventually give them some, they suck it all up quickly (within a day or two). Then they starve again. This cycle of food and starvation is bad for plants and stops them growing properly or at all.

Liquid plant fertilisers remain in the water until used by plants or algae, or until they are diluted out with water changes.

If you are using a liquid aquarium plant fertiliser, you should monitor the main ingredient with a test kit. Most are iron based and you check the iron levels in the water with an iron (Fe) test kit. Keep iron levels at 1mg/Ltr (1ppm).

When you first start adding a liquid aquarium plant fertiliser, the plants will normally use it all up within a day or two of being added to the tank. So a lot of people will add a half dose of fertiliser every couple of days for the first few weeks. Then they add it twice a week for a few weeks, and then a full dose once or twice a week after that. This allows the plants to take up the nutrients and get to a point where they have drawn in enough fertiliser to keep them going and they don't remove it all in a day.

Whenever adding aquarium plant fertiliser to aquariums, you should always do a huge water change every week to dilute any excess nutrients from the water. This prevents overdosing if the plants have not used up all of the nutrients before you add more.
 
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That's greatly explained ! Thanksssss !
Were repeated/divided daily doses (in french "doses filées") are a good way to fertilize or not ?
 

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I make my own fertilizer. And have learned that Fertilizer depletion and ineffectiveness both occur in a planted aquarium. In my experience depletion is the biggest issues. As plants grow they remove fertilizer nutrients from the water. Eventually one or more of the 14 nutrients runs out. When that happens do a water change to remove the excess nutrients and dose fertilizer. If all 14 nutrients are in balance with each other only one dose of fertilizer per week is all you need.

Unfortunstely most fertilizer assume your water has some nutrients and as a result they don't include all 14 of the nutrients plants need. As a result some fertilizer will not work at all for some people and ,or only work for a few days for others depending on what is in your tap water and substrate.

In my case ib my 5 gallon shrimp tank I could could not get any plant growth with Aqueon , flourish comprehensive, and CSM+B fertilizers. I am using RO water with an inert substrate. So my water and substrate didn't supply any nutrients which the fertilizers I tied fertilizer were lacking nutrients that are sometimes suppliedbytap water. I eventually gave up on buying fertilizers and just made my own. correcting all nutrients deficiency I had experienced. it was the best decision i had made,Now most plants I put in the tank will grow. and I only dose fertilizer once a week.

You tap water will also determine how long it stays effective. your fertilizer can become ineffective due to interactions with your tap water. Some nutrients don't stay water soluble for long, Mainly iron and Manganese. Iron is sensativeto PH. Iron EDTA is a popular iron salt for fertilizers. However it is only stable in water with a PH of 6.5 or less. Above that level it breakdown to iron oxide which is not water soluble and is not usable to plants. Most aquariums have a ph that is above 6.5. Other fertilizers use iron gluconate. PH has no effect on it. but bacteria can quickly consume the gluconate leaving behind iron oxide which is not usable by plants. IN some fertilizers manganese sulfate will interact with calcium carbonate (KH) resulting in manganese oxide which is unusable by plants. PH and KH can probably affect other nutrients in fertilizers but I have not seen those interactions yet. My RO tank runs at a very low KH level (1 or 2 degrees) with a ph of 7. So I use Iron DTPA in my fertilizer which is stable tabour a PH of 8 I only need 0.02ppm of iron per week to get good plant growth. Manganese sulfate is usable in my low KH tank water.

If you look on line there are many people recommending a iron level of 1ppm. The 1ppm recommendation is mainly due to iron gluconate in fertilizers. In other cases the higher iron dose is used to compensate for anutrient deficiency. Many people in with high tech tanks use CSM+B as a microfertilzier. In addition to using Iron EDTA it also supplies insufficient amount of zinc. So even if you have the correct water PH you need to increase the dose CSM+B to get enough zinc. That works out to about 1 to 4 ppm of iron. Iron appears to become toxic at about 2 to 3ppm.
 
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Colin_T

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Is a small amount of fert every day is a good way to fertilize (instead of one full dose once a week) ?
Adding a small amount (lower dose rate) of aquarium plant fertiliser every day can help, especially during the first few weeks. This is when the plants are going to use lots of it. They need to build up their reserves and repair cells and once they have done that, then they can grow.

You can also add a full dose and monitor the iron levels. If the iron level is 0ppm after 24 hours, I added another dose. I did this daily until the iron levels didn't drop to 0ppm in one day and then I added fertiliser when it was needed. And every week I did a massive 75-90% water change and gravel clean to remove excess nutrients that might not have been taken up by the plants.

If you are adding aquarium plant fertiliser, make sure you don't have carbon in the filter because it will remove iron and some other elements.
 

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What do you think about Tropica© Specialized Nutrition ? Or PPSpro fertilizer ?


Its impossible for me to comment on Tropica Specialized. Thewebsite doesn't list anything about what is in the bottle. I generally would not recommend product if I don't know anything about it.

As to PPS pro fertilizer it is nothing more than the typical Estimative index fertilizing methode commonly used on most high tech aquariums. In this methode you buy the macronutrients separately to mix your own macro fertilizer (N,P,K, Ca, Mg). and then buy a micro mix to supply the remaining nutrients. Their jar of micro fertilizer is nothing more than the CSM+B micro fertilizer. Like I mentioned earlier it works best in water with a PH of 6.5 or less and doesn't have much zinc in it. I used this veryproduct in my tank and it didn't work because my PH was wrong and there isn't enough zinc.

If you co to this fertilizer calculator you can enter your tank size and select a fertilizer from a list of premixed fertilizers and it will list out the nutrients levels that results fromm your dose. Before I decided tomato my own fertilizer I looked at a lot of fertilizers on it. only one came close to the nutrient balance I was looking for. That is TNC fertilizer. A british product that isn't available were I live. So I have never tried it.but it might be available in your location.
 

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