When to start dosing with plant food?

[KreativJustin]

Hello everyone, so I have invested into some plants. I currently have amazon frogbit (about 2 weeks I believe) and it has grown and replicated tremendously quick with nice beautiful roots. I just added water wisteria (it was fully submerged when I bought it from the aquarium store, in a pot - not the plastic tube like petsmart). I put a root tab in the sand with the wisteria, but have never fed the frogbit. So my question, when do I start putting in food for plants, is there a rule of thumb or a water test parameter that I need to make sure is good?

I have just direct sand, nothing special added to it, which is the reason I did a root tab for the wisteria. I tried plants one time and ended up over feeding on the root tabs and plant food, combined with the eco complete substrate, and I ended up having WAYYYYY too much nutrients going on at one time and it ended up in bad algae. So I am heavily trying to avoid doing that again.

Thanks for the heads up everyone.

[Caliban07]

The frogbit will show signs of deficiency before the submerged plant because the frogbit is a floating plant that has access to atmospheric levels of co2 and is closest to the light fixture. So if you keep the frogbit happy there will undoubtedly be enough nutrients for the plants underwater.

Do you have some pictures of your frogbit?

[KreativJustin]

I shared a pic after the roots took off: https://www.aquariumadvice.com/forum...it-381068.html

I'll post a new updated pic tomorrow.

[Colin_T]

Plants should be fertilised from the day you get them so they can recover from being moved and start growing again.

I used a liquid iron based aquarium plant fertiliser (Sera Florena) and monitored the iron level in the water with an iron (Fe) test kit. I kept the iron level at 1mg/l (1ppm) and did a big water change each week before adding more fertiliser.

Some aquarium plant fertilises have nitrogen and phosphorus in. You don't want these in a normal aquarium. Nitrogen is poisonous to fish, hence the reason we have a filter on the tank (to convert ammonia into nitrite, and nitrite into nitrate). The fish, shrimp, snails and anything that rots in the water produces ammonia, which is a form of nitrogen and is the easiest for aquatic plants to use. Nitrogen encourages leaf growth.

Phosphorus is used by terrestrial plants to develop a decent root system and to thicken the cell wall. Most aquatic plants have small root systems and take in most of their nutrients via their leaves, so phosphorus isn't needed in an aquarium. Phosphorus is commonly linked to algal and Cyanobacteria blooms in rivers, lakes and aquariums. High levels of phosphorus are poisonous to fish and other aquatic organisms.

[KreativJustin]

Originally Posted by Colin_T

Plants should be fertilised from the day you get them so they can recover from being moved and start growing again.

I used a liquid iron based aquarium plant fertiliser (Sera Florena) and monitored the iron level in the water with an iron (Fe) test kit. I kept the iron level at 1mg/l (1ppm) and did a big water change each week before adding more fertiliser.

Some aquarium plant fertilises have nitrogen and phosphorus in. You don't want these in a normal aquarium. Nitrogen is poisonous to fish, hence the reason we have a filter on the tank (to convert ammonia into nitrite, and nitrite into nitrate). The fish, shrimp, snails and anything that rots in the water produces ammonia, which is a form of nitrogen and is the easiest for aquatic plants to use. Nitrogen encourages leaf growth.

Phosphorus is used by terrestrial plants to develop a decent root system and to thicken the cell wall. Most aquatic plants have small root systems and take in most of their nutrients via their leaves, so phosphorus isn't needed in an aquarium. Phosphorus is commonly linked to algal and Cyanobacteria blooms in rivers, lakes and aquariums. High levels of phosphorus are poisonous to fish and other aquatic organisms.

Is there any other brand you recommend other than Sera Florena?

[Caliban07]

Originally Posted by Colin_T

Plants should be fertilised from the day you get them so they can recover from being moved and start growing again.

I used a liquid iron based aquarium plant fertiliser (Sera Florena) and monitored the iron level in the water with an iron (Fe) test kit. I kept the iron level at 1mg/l (1ppm) and did a big water change each week before adding more fertiliser.

Some aquarium plant fertilises have nitrogen and phosphorus in. You don't want these in a normal aquarium. Nitrogen is poisonous to fish, hence the reason we have a filter on the tank (to convert ammonia into nitrite, and nitrite into nitrate). The fish, shrimp, snails and anything that rots in the water produces ammonia, which is a form of nitrogen and is the easiest for aquatic plants to use. Nitrogen encourages leaf growth.

Phosphorus is used by terrestrial plants to develop a decent root system and to thicken the cell wall. Most aquatic plants have small root systems and take in most of their nutrients via their leaves, so phosphorus isn't needed in an aquarium. Phosphorus is commonly linked to algal and Cyanobacteria blooms in rivers, lakes and aquariums. High levels of phosphorus are poisonous to fish and other aquatic organisms.

Hi Colin

Nitrogen toxicity is dependent on it’s form and most, if not all fertiliser is made for aquariums contains nitrates. Nitrates do not get near the toxic level to cause harm in an aquarium and you can 100% convert ammonia to nitrate in an aquarium without using a filter at all.

Phosphorus is an essential nutrient required by all plants in order to build new tissue and the molecule that allows a plant to turn co2 in to sugar is Ribulose Bi-phosphate. There is no bearing on whether the plant is above or below water. Phosphorus is a macro nutrient and is needed in large amounts by plants along with potassium and nitrogen.

Whilst Phosphate eutrophication has been strongly linked to algae in natural water where species and parameters vary, the same cannot be correlated with aquariums.

Phosphates help plants to grow and a tank chock full of healthy plants is the true algae deterrent.

Having said that you don’t generally need to add nitrogen or phosphates in most tanks because the fish and food supply decent amounts.

OP- if you inspect the frogbit leaves and they are pale and or small you can add an all in one fertiliser. You can use floating plants to control fertiliser input so that there is no reason to overdose. The roots won’t tell you much but the leaves will.

[KreativJustin]

Cool, I'll upload pics tomorrow.

[Colin_T]

Originally Posted by KreativJustin

Is there any other brand you recommend other than Sera Florena?

I have no idea what aquarium plant fertilisers are available now but if you look for one that contains iron and other trace elements, it will be a good start. Most of the macro elements [NPK - (N) nitrogen, (P) phosphorus, (K) potassium] will come from the fish and food.

[KreativJustin]

Here are the pictures.. the ones that are mis-colored are the original ones, and they have actually gotten out of the direct light and get indirect light now. The other ones that are really green are the new ones.

[Caliban07]

They are doing very well. Much better than mine but I have a very large plant mass so my tank is probably running on reserves of certain minerals at the moment.

[KreativJustin]

Yours tank is beautiful looking.

So should I avoid adding any nutrients just yet, or start now and add when it seems like it is lacking?

I was thinking Seachem Flourish.

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

[Caliban07]

I wouldn’t dose yet if I were you personally. The frogbit will be sucking nutrients up faster than the other plants because it’s floating. Floating plants have access to 400 parts per million of carbon dioxide in the atmosphere and they are directly under the light fixture where the light intensity is at it’s highest.

Light intensity drives photosynthesis which means that in order to stay healthy, the frogbit needs to ‘breathe’ in co2 and take in as much nutrients as possible to keep up with the demand of the light shining down on it.

The plants underwater can’t ‘breathe’ the co2 in. They don’t have stomata when they are underwater. The co2 is pushed in to the leaves. Thats why they have a thin cuticle. Not only that, an average aquarium has low levels of carbon dioxide and the plants are further away from the light.

This means that underwater plants simply don’t need as many nutrients as frogbit and so if the floating plants are happy and show no sign of nutrient deficiency then there should be more than enough nutrients to support the underwater plants.