# Substrate fert vs liquid fert



## Borntofish (Nov 30, 2007)

Hi All,
I am new to the forum and very pleased with all the great info on the forums!! Anyway, I recently spoke with someone from plantedaquariums.com regarding fertilizers. I am fighting an algae problem in the tank, both green spot on the glass and and black/brown algae on the leaves. Anyway, he suggested that I use only substrate fertilizers instead of liquid. He feels that the majority of plantes absord nutrients through the roots so placing liquid ferts is only food for algae. I am thinking a combo of the two may be the best answer but I would love to hear evryone's thoughts and experience!


----------



## TNguyen (Mar 20, 2005)

Both method for me. Depending on plants selection, If i use lots of foreground plant then I do the substrate. With stem, I prefer liquid.


----------



## trenac (Jul 16, 2004)

From what I have learned over the years the majority of plants absorb their nutrients through the water column, so liquid ferts is a must. Only a few plants such as swords & crypts absorb nutrients through their roots, which in this case a substrate fertilizer would work. However, I have found dosing through the water column with liquid ferts is plenty of nutrients for the root feeders also. 

Green spot algae usually grows when their is a lack phosphates in the water column. The black algae you speak of is probably black beard algea, which is caused by a lack of C02. Brown algae or diatoms is commonly found in newer setups, low light tanks & tanks without C02.


----------



## Homer_Simpson (Apr 2, 2007)

My understanding that aquatic plants can feed either through the roots or the leaves and will adapt either way. If you Google this subject, you will see many references to people who succesfully grew aquarium plants with a highly enriched substrate and equally ones that succeed with nothing more than plain old pool filter sand, inert kitty litter, etc.

I just set-up a low maintenance(no c02, mostly low plant lights, and only 10 watts compact fluorescent lighting) 5 gallon tank where plant growth exploded in 3 weeks. Some diatom algae began forming on a java fern leaf and the Amano shrimp that was in the tank took care of that. No sign of any other algae whatsoever. I was forced to do major trim 2 weeks after the tank was set up and another one after one week. I used very minimal if any water column fertilizers and the only thing that can explain this, through the process of elimination, is the use of Seachem Onyx Sand, mulm, leonardite, and peatmoss substrate. So I am not entirely convinced that a rich substrate does not make a difference. And the benefits of a rich substrate may also explain why people get such good plant growth with ADA Amazonian I and Amazonian II aquarium substrate.



trenac said:


> Brown algae or diatoms is commonly found in newer setups, low light tanks & tanks without C02.


My 40 gallon has been running 9 years has lighting from 2 55 watt AH britelight kit(which should ensure more than sufficient light), and has 30 ppm c02(as measured by a drop checker) from a pressurized c02 system. Despite this, I am still fighting a major diatom algae bloom go figure. Perhaps, this is what is known as one of those "exceptions to the norm."


----------



## trenac (Jul 16, 2004)

Homer_Simpson said:


> My 40 gallon has been running 9 years has lighting from 2 55 watt AH britelight kit(which should ensure more than sufficient light), and has 30 ppm c02(as measured by a drop checker) from a pressurized c02 system. Despite this, I am still fighting a major diatom algae bloom go figure. Perhaps, this is what is known as one of those "exceptions to the norm."


I'm sure that diatoms can show up in about any setup. But from personally experience & reading, I'm just saying it is more common in particuliar setups.


----------



## hoppycalif (Apr 7, 2005)

El Natural tanks rely upon the substrate for feeding the plants. Inert substrate, non-CO2 tanks can use either water column or substrate feeding. But, high light intensity demands water column feeding especially for nitrates, which are the most needed nutrient after CO2. That is how I understand it, anyway. When we drive the growth of our plants to as high a growth rate as we can get, by using high light intensity, there just isn't any way the plant roots can provide that much nutrients. My experience with sword plants has been that they will grow well with either substrate or water column feeding, but they grow by far the fastest with water column feeding.


----------

