Small 3.5 gal beginner CO2 help!! - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old 07-31-2019, 05:02 AM Thread Starter
PTrader: (0/0%)
Join Date: Jul 2019
Posts: 1
Small 3.5 gal beginner CO2 help!!

I’ve recently started a 3.5 gallon planted tank and I bought the API CO2 booster. I’m not sure how much liquid carbon to add to the tank or how often. The bottle says to add daily but I’m worried the carbon will start to add up considering how small my tank is. The dosages are 1mL/ 10 gal. Please help!!
sofiiiiuh is offline  
Sponsored Links
post #2 of 3 (permalink) Old 07-31-2019, 06:00 AM
Planted Tank Enthusiast
PTrader: (0/0%)
Join Date: Apr 2019
Location: 67212
Posts: 700
1/3=.3ml daily max, I’d start with .1 and work way up till you see growth you like. You also need to be adding a full spectrum AIO fert also. Without ferts plants can’t process carbon.
DaveKS is offline  
post #3 of 3 (permalink) Old 08-06-2019, 12:40 PM
Algae Grower
PTrader: (0/0%)
Join Date: Aug 2019
Posts: 22
I have a 2.5 and use the same liquid co2. 1/10 = x/2.5.... x = .25ml which is 5 drops per day. But the margin for error is smaller in small tanks. I make sure I have enough fertilizer so that I can adjust light and co2 to get the growth I want then I cut fertilizer, light and co2 down a bit so that the tank is in a somewhat of a limited resource state so growth is slower. I use 2 drops per day on my medium planted tank of co2. But I use co2 because I dose, dosing without proper nutrients for your plants makes your tank very susceptible to algae because the plants cannot grow so the co2 you are adding is going to aid the growth of algae instead of the plants.

Continuing on about nutrients/fertilizer... you need macro and micronutrients for your plants to grow. You can give your plants plenty of Co2 but if the tank is deficient in one or more macronutrients the plants will not use the carbon from co2 or any other macronutrient (nitrogen, potassium, phosphorus) to the degree they normally would either.

This is because a plants growth is determined by the limiting (deficient) nutrient [Liebig's law of the minimum]. So, if you are for example, deficient in potassium, which isn't found in plant or animal waste or in tap water plant growth will be difficult. Because of this lack of growth, your plants will also not be consuming the other macros like nitrogen, phosphorus, and carbon. But if you give them enough potassium they will then begin to grow and absorb and utilize the other macronutrients again. To side track... this can create a problem of adding co2 and getting algae and then believing you are adding too much co2 when in reality your plants are missing a macronutrient and aren't utilizing the co2 that's available which is going to algae is instead. But correcting the deficiency allows the plants to grow, take up co2 and out compete the algae, eliminating it.

I use separate macronutrients and flourish comprehensive and flourish Iron for micronutrients but you can buy all in one macro+micro nutrients but for a smaller tank I just think more control over what you are adding is necessary in a smaller tank due to that small margin of error and the fact that any tank with unbalanced nutrients is susceptible to algae that will take advantage the second they can.

I dose 2 drops co2, 5 drops iron a day (recommended dose), flourish comprehensive 4 drops once a week (recommended), potassium 4 drops a week (recommended). As far as nitrogen and phosphorus....I dose Phosphorus based what my phosphate test kit shows my current level is and my nitrate(nitrogen) reading because I know the ratio the two should be to each other. If nitrate test shows 0ppm I add flourish nitrogen to get to 5-10ppm. ratio between nitrogen and phosphate should be 10:1. I don't have to do the phosphate test every time I dose now as after I did it for a few months I became familiar with how much phosphates my plants take up. so I add 2 drops a week of phosphate. The general ratio for macronutrients is something like this: 1P:10N:20K (phosphorus, nitrogen, potassium)

Last edited by nothreat33; 08-06-2019 at 12:59 PM. Reason: i keep wanting to add mroe
nothreat33 is online now  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome