Are nitrates and phosphates bad for planted aquariums?

[Nicki Gaga]

If they are essential for plant growth, why do many aquarium plant fertilisers leave them out? And are they actually necessary for planted tanks?

 

[Luv4dan]

I think it's because if you have fish you should already have nitrates in the tank so you shouldn't need to add more. If you have a lot of fast growing plants, however, they might use up all the nitrate and then you would have to add more. Too much phosphate supposedly creates algae problems, but I've also read it's not true so I'm not sure.


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[Nicki Gaga]

I mean, it's because the lower leaves are rotting on my elodea but my elodea is growing algae on itself. What does that mean? Does it mean it's getting too much light or too little light?

 

[Rodeo one]

Hi Nick. What I ve learned from experienced people here on the Forum is.....
Planted tanks should have a phos of 1-2 & Nitrates at 10-20.
Do you have liquid test kits ?
Algae is usually from too much light. Try running yours for 6 hrs .
Does your tank get indirect sunlight?


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[BBradbury]

Nitrates and Phosphates

If they are essential for plant growth, why do many aquarium plant fertilisers leave them out? And are they actually necessary for planted tanks?

Hello Nick...

Nitrates are the end form of nitrogen from dissolved fish wastes. If you have a decent number of fish in the tank and feed them a balanced diet, you have nitrates in the water. If you feed flaked fish food, you have a source of phosphate. Phosphate is one of the first ingredients in most flaked fish foods.

Pretty simple.

B

 

[Rivercats]

Most fertilizers in general contain mostly micro nutrients which do not naturally occur like nitrates and phosphates can in an aquarium. Whether you need macro nutrients such as nitrates, phosphates, and potassium (which is often needed as it also does not naturally occur) depends on your tanks weekly levels, type and amount of plants, amount of lighting, and whether you use CO2 or a liquid carbon. Algae becomes an issue when lighting, CO2, and ferts are out of balance. As already stated running lighting too long is often the root of algae issue but usually it is a combination of things. Also what type of algae are you getting?