Friday, January 18, 2008

Ferts & c02

General guide to EI dosing for a 125L tank

With EI it is suggested that each chemical is added separately or at least until you get the feel for the dosing then may be all the ferts can be added into one bottle. Those listed below are for macro nutrients dosing. For trace mix use “tropica plant nutrition” or “seachem flourish”

Potassium Nitrate - 40g to 500ml of water and adding 10ml per 100L of water would give you 5ppm NO3.

Potassium Phosphate - 15g to 500ml of water and adding 5ml per 100L of water would give you 1ppm PO4.

Potassium Sulphate - 55g to 500ml of water and adding 10ml per 100L of water would give you 5ppm K.

Magnesium Sulphate - 70g to 500ml of water and add 50ml once a week per 100L of water - this would give you 7ppm Mg.

Tank volumes are in US gallons.

To convert to UK gallons multiply these figures by 0.83 Your tank is 125L=33 us galls.

20-40 Gallons (76-152 litres)

20ml solution or 1/4 tsp KNO3 3x a week

12ml solution or 1/16 tsp KH2PO4 3x a week

5ml solution or 1/16 tsp K2SO4 3x a week5ml or 1/16 tsp traces 3x a week

Sunday ....... 50% water change. Add KNO3, KH2PO4, K2SO4

Monday....... Add traces

Tuesday...... Add KNO3, KH2PO4, K2SO4

Wednesday...... Add traces

Thursday...... Add KNO3, KH2PO4, K2SO4

Friday...... Add traces

Saturday...... Rest day


You will need the ferts which I link you to from AE. KNO3,KH2P04,K2SO4 and magnesium Sulphate 4 x 500ml bottles.

Mix ferts as per above and dose as above

Checking c02 levels

All plants will benefit from c02 in any tank, be it low light or high light.

The one problem people tend to have is how to check how much c02 is in the tank. This can be done one of two ways.

1. The most common method of checking c02 is taking the pH/kH read and checking them against a c02 table, the aim is to have a reading within the green boxes. This method is fine and has been used for a great many years, but, this method has ONE MAJOR problem, it relies on the water column having “NO BUFFERS” in the water. If any buffers, ph up or pH down etc or even p04 are in the water then the reads will not give a true account of the total c02 in the water.

2. The more favoured and more accurate way of checking c02 is by using a drop checker and a 4dkh solution. This when placed in the tank will show by a blue, yellow or green color what the c02 levels are.
Blue = too little. Yellow = too much. Green = OK.
Green indicates a c02 level of 30ppm. There are other dkh solutions that can be used 3 & 5dkh which give higher or lower reads than 30ppm depending on the level you want but 30ppm is the more natural for a planted tank.

Turn drop checker upside down and half fill the ball (approx 5-6 drops) of 4dkh solution
2. Add 1-2 drops of APIs low pH solution bromo blue) the amount of bromo blue will not affect the read only the deepness of the color.
3. Turn the drop checker the right way up, being careful not to spill the solution.
4. Place the drop checker in the tank so it is visible.
5. Approx 1hr after you place the drop checker in the tank you should see the color of the regent changed or starting to change. After 2hrs you should be able to read the color as is to get the correct level of c02 in the tank

Drop checkers & 4dkh solution can be found here:

So how does this little glass ball work?
A drop checker is basically a reservoir that holds an indicator solution, 4 deg° KH standard and a pH indicator, “bromo blue”(found in API low pH test kit) and an air space that separates the aquarium water from coming into contact with the indicator solution.

When CO2 is injected, and the aquarium water contains more CO2 than the indicator solution, the injected CO2 will outgas from the aquarium water into the airspace inside the drop checker. The CO2 in the air space of the drop checker will then be absorbed into the indicator solution (bromo blue) inside the drop checker. That absorption of CO2 into the indicator solution will then lower the pH, which in turn will change the color of the pH indicator.

When CO2 is NOT injected into the aquarium, and the indicator solution contains more CO2 than the aquariumwater, the CO2 will outgas from the indicator solution into the airspace inside the drop checker. From the airspace inside the drop checker the CO2 will get reabsorbed into the aquarium water. The out gassing of CO2 from the indicator solution inside the drop checker will raise the pH of the solution (bromo blue) which will change the color of the pH indicator.