# Fertilizers and Co2: How necessary are they?



## Odessabarb1049 (Aug 31, 2017)

Okay, I just joined this forum about 5 minutes ago to ask one question. I'm planning to switch my non-planted tank into a planted one, and I've done a TON of research on it. I have a 20 gallon tank with medium-good lighting, a good filter, I've planned out which nutrient-rich substrate in going to mix with my gravel, but two things remain. The Co2 and nutrients I may or may not need to add. I know how to inject the Co2 into the tank, and know which ferts I may need to use, but I'm not sure if I really need to use the Co2 and ferts. This tank had been up for about 6 months now, with a pleco, Odessa Barbs, and a Molly that all make a decent amount of waste. So, again, I'm just wondering if extra Co2 and nutrients are necessary for plant growth. Also, what are the best plants for a beginner like me? Thanks so much, any imput will be appreciated! (I tried to make this as short as possible to spare you all from reading an essay)


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## MsJenny (Aug 21, 2017)

I'm still trying to figure that out. 
The first picture is if my 12 gal high-tech (ADA dirt, power sand, bacteria powders, high light, CO2). Within two weeks of setting it up 2/3 of my plants melted away! The entire tank was planted! 

The second picture is of my 4 gal low tech tank. The substrate is made up of mixed sand and Fluval soil and it's about a year old. I used a 13W Fluval fluorescent bulb. I used Excel about once a month, if I remember. Rarely change the water and simply replenish whatever has evaporated. The only indication I have that tell me it's doing alright is that the AR var. and AR mini haven't melted. Compare that to the high-tech where I've lost make the AR mini and all 5 AR var. the tonina lotus is still alive -this is the tank I use to move dying plants into to revive them.


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## Karackle (Dec 11, 2007)

The short answer is definitely not. 

Low tech tanks often don't have fertilizers added to them, and certainly not CO2 injected. It depends on who is defining low tech, some will say DIY CO2 counts as low tech, but others (like myself) are of the feeling that any added CO2 is not low tech. 

Not adding ferts or CO2 changes to some extent what plants you can grow, but if you look at the low tech can be lush too thread and low tech plant list you can get a good idea of what plants work well  A good place to start is with java ferns, anubias, cryptocorynes (crypts) (many varieties of all 3), and bolbitis.

Personally, my tanks are all super low tech. Crypts get most of their nutrients through their roots so now that my planted tank substrate is getting old I do add root tabs under the crypts about twice a year, but otherwise I rely only on the fish to provide fertilizer for my plants. I also keep my tanks on the slightly overstocked side to keep the plants happy, but because the plants do grow well, the water parameters are always excellent, so the fish are happy  I got into planted tanks to make the fish happier, so it's definitely important to me that the tanks are stable and parameters are good. 

So again, no it is definitely not necessary to add fertilizers (caveat...once your nutrient rich substrate gets older you may need to supplement with root tabs occasionally for heavy root feeders like crypts...if and when this becomes necessary will depend on what substrate you use, for example I've heard mineralized topsoil type substrates don't last basically forever). And you definitely don't need to add CO2.


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## AbbeysDad (Apr 13, 2016)

Fish food and fish waste to a point can organically feed plants...after all, that's how they grow in nature! Now a newly setup tank is fairly sterile, so ferts are [even] more important. In the well established tank, there may be enough nutrients to sustain plants, however some slight fertilization will likely be a benefit to ensure plants have all the various nutrients they need.
Injected CO2 will accelerate plant growth, but many plants grow just fine (albeit slower) in low tech tanks w/o CO2.


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## JJ09 (Sep 11, 2014)

I would say just try it and see... and if the plants are struggling, add ferts, but you don't have to use C02. My low tech tank-








doesn't have nutrient-rich substrate, I add root tabs about once a month. I thought I had enough fishes to supply what the plants need, but it wasn't so- as soon as I started dosing ferts (I do 1/3 EI) saw dramatic difference in my plants. Every now and then I start thinking: surely I have enough mulm built up I can quit doing root tabs, or cut back on ferts. But if I relax my schedule, the plants slowly start to look poorly. This just happened last week- I realized it had been six weeks or more since I'd added root tabs. I put some in, and the next week plants I hadn't realized were declining (because the change was slow) suddenly looked really healthy again. So I figure I have to keep doing that.


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## IntotheWRX (May 13, 2016)

fertz probably yes. a pour once every week or two. $6 bottle could last you a while. 

co2, not needed but wow the tank sure looks good when co2 is injected into the water.


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## freshestemo412 (Aug 19, 2016)

MsJenny said:


> I'm still trying to figure that out.
> The first picture is if my 12 gal high-tech (ADA dirt, power sand, bacteria powders, high light, CO2). Within two weeks of setting it up 2/3 of my plants melted away! The entire tank was planted!


Did you do a dry start? The plants might have been grown emersed thats why they melted. Ive experienced this in my 12 long as well. My Monte Carlo and UG went to hell real quick after I flooded. I posted everything in my journal.

After that, and getting new plants that were grown underwater, and now giving them time to adjust Im seeing pretty good growth.



As for the question in general, no you dont need both but I would recommend fertilizers for sure. I would start off doing once a week and then depending on how your plants react adjust from there.


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## Jeff5614 (Dec 29, 2005)

https://barrreport.com/threads/step-1-define-your-goals.2864/

https://barrreport.com/threads/step-2-chose-a-method-and-learn-it-well.2865/


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## houseofcards (Mar 21, 2009)

Jeff5614 said:


> https://barrreport.com/threads/step-1-define-your-goals.2864/
> 
> https://barrreport.com/threads/step-2-chose-a-method-and-learn-it-well.2865/


Yep those are excellent reference. 

As far as using co2, alot obviously depends on the light your using. co2 makes it easier to grow any plant. With better growth there is less likelihood of algae issue.


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## Surf (Jun 13, 2017)

CO2 is prescient in the air but if your lights are very bright you might get a dangerous PH increase as the plants can deplete water faster than CO2 can get back in. Fertilizers in contrast are only depleted and only go up if you add them or when you do a water change. If your water has all the minerals need which is frequently not the case, fertilizer is not needed. 

Most low tech tanks use lower light levels to prevent PH increase, and many are fertilized. High tech tanks add CO2 and have brighter lights for faster plant growth and fertilizer is required. It is your choice as to which type of tank you want. Estimative index type fertilizers will work for both types of tanks. For both types of tanks a water change is needed to prevent minerals from food building up in the water. People typically do 30% to 50% water change weekly.



> I'm still trying to figure that out.
> The first picture is if my 12 gal high-tech (ADA dirt, power sand, bacteria powders, high light, CO2). Within two weeks of setting it up 2/3 of my plants melted away! The entire tank was planted!


Most fertilizers on the market don't have calcium even though it is a vital macro nutrient. In is assumed that soil and water have enough that it's not needed in the fertilizer. With an aquarium with high light and CO2 the calcium available in the water and substrate may not be sufficient to support rapid plant growth. That leads to calcium deficiency and potentially plant death. With a low tech aquarium it is possible to run one without fertilizer and minimal water changes because the nutrients in the fish food keep the nutrient level up and some nutrients settle into the substrate. The low light level and lower CO2 levels slow plant growth enough that the aquarium never gets depleted of nutrients. 

In addition to calcium, sulfur and chlorine (two other vital plant nutrients) are often also omitted from most fertilizers. Chlorine deficiency is extremly unlikely in most aquarium. sulfate GH boosters like Seachem Equilibrium contains magnesium, calcium, and sulfur. Other GH boosters contain calcium magnesium, and chlorine. I would recommend trying seachem Equilibrium in addition to EI fertilizers.


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## MsJenny (Aug 21, 2017)

Surf said:


> CO2 is prescient in the air but if your lights are very bright you might get a dangerous PH increase as the plants can deplete water faster than CO2 can get back in. Fertilizers in contrast are only depleted and only go up if you add them or when you do a water change. If your water has all the minerals need which is frequently not the case, fertilizer is not needed.
> 
> Most low tech tanks use lower light levels to prevent PH increase, and many are fertilized. High tech tanks add CO2 and have brighter lights for faster plant growth and fertilizer is required. It is your choice as to which type of tank you want. Estimative index type fertilizers will work for both types of tanks. For both types of tanks a water change is needed to prevent minerals from food building up in the water. People typically do 30% to 50% water change weekly.
> 
> ...


A few months ago I was testing out Epsom salt and a combined calcium/magnesium/potassium vitamin and testing out how various combinations changed the Ph, Gh and Kh of RO water. After I was done I poured some of the water into my 12g planted tank and I noticed that almost immediately the color of my plants intensified, especially the reds. I attributed the color change with the addition of the small amount of Espson salt and vitamin I added but I couldn't point to a single element as having the most effect. I also didn't understand why there was such a drastic change since I had followed a strict dossing regimen which included iron for the red plants and other ferts include potassium and I'm pretty sure magnesium as well. What you're saying makes sense now, they've beed lacking calcium.

I don't keep shrimp in my 12 gal (high tech) tank but from now on I'm going to make sure and add Gh+/Kh+ and test the water to verify Gh/Kh levels in this tank just like I do with my shrimp tanks.



freshestemo412 said:


> MsJenny said:
> 
> 
> > I'm still trying to figure that out.
> ...


No I didn't do a dry start. Most of the plants that melted were from in-vitro cups. However I had left over plants from the same cups which I planted in one of my other eatablished low-tech tanks and those plants are thriving. So I dont think that in that case the plants in my 12 g melted because they were growing immersed. Other easy plants melted without explanation. While others like many of my red/pink rotalas and flamingo crypt thrived. This all before adding ferts. 

It's been suggested that I add trace minerals, which I have done since and my plants are significantly stabilized although I am adding new plants slowly by adding just one stem and testing whether it survives the current conditions of the tank.


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## Surf (Jun 13, 2017)

> A few months ago I was testing out Epsom salt and a combined calcium/magnesium/potassium vitamin and testing out how various combinations changed the Ph, Gh and Kh of RO water. After I was done I poured some of the water into my 12g planted tank and I noticed that almost immediately the color of my plants intensified, especially the reds. I attributed the color change with the addition of the small amount of Espson salt and vitamin I added.


The vitamins probably had no effect on your plants. Most people don't fertilize with vitamins and they are not listed as essential plant nutrients. Epsom salt is magnesium sulfate, calcium and potassium are all Macro nutrients. There are 6 nitrogen, phosphate, potassium, calcium, magnesium, and sulfur. You does the water with 4 of them. Fish waste may have provided the other 2 (nitrogen and phosphate).


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