18/09/2014
Planted aquariums vs shrimp tanks --- PART III
Apologies to everyone for the long interval between tutorials. The Shrimp Doctor has been traveling recently for the past month. The next part of our mini tutorial series will be addressing CO2 supplementation in a planted shrimp tank.
Why do we need co2?
Plants combine CO2 with water (H2O) to produce oxygen and glucose. All plants, terrestrial or aquatic, will require CO2 for photosynthesis and growth. In an aquarium without CO2 injection, the CO2 level in the water is usually at equilibrium with the atmosphere (at about 6-7ppm). This level of CO2 is sufficient for low-tech plants which require less light. However, in heavily planted tanks or tanks with high-tech plants (such as HC or UG), CO2 injection is required to supplement the amount of CO2 as these plants start to use up most or all of the CO2 available.
Supplementing CO2 will result in healthier growth of plants, along with a reduction in the ability of algae to grow and reproduce, since the plants are growing to their full potential. CO2 is just as good for algae control as it is for general plant growth, assuming you are injecting it properly and sufficiently. CO2 deficiency will re**rd plant growth, especially that of high-tech plants.
How to measure CO2
So how do we know how much CO2 is there available in our tanks? CO2 is measure in parts per million (ppm). In a healthy planted aquarium with a pH of around 6.0, the CO2 level is usually kept at between 15-30ppm.
There are many ways to measure CO2 levels. The most common method is to measure pH and kH values of the tank and use it to formulate the amount of CO2 in the water. This is the link which you can use to input your values and get your CO2 reading, http://www.fishfriend.com/aquarium_co2_calculator.html. However, this method is only accurate if CO2 is the only variable that affects pH in the tank. For many planted or shrimp tanks, we use specific soil to lower pH to a reading of about 5.8-6.2. This will render CO2 readings from the above method to be less accurate.
An accurate way of measuring CO2 concentration is by a drop checker. A drop checker is basically a pH test, but not for your tank water. It measures the pH of your drop checker solution, which indicates CO2 levels. There is an enclosed air chamber trapped between the tank water and the drop checker liquid. The CO2 in your tank will diffuse into the trapped air, and then into the drop checker compartment. It will do this until the water in the tank and the water in the drop checker reach equilibrium. This means that there is an equal concentration of CO2 in both chambers of liquid. CO2 is the only variable affecting the pH in the drop checker, therefore pH in the drop checker is directly related to CO2 levels in both the tank. The colour of the drop checker solution indicates the level of CO2 in the tank.
Blue - not enough CO2
Green - 30ppm CO2 (target level)
Yellow - too much CO2, dangerous for inhabitants
The following link shows how a drop checker is being set up. http://www.youtube.com/watch?v=skE2zBWw7qc
CO2 supplementation in a planted shrimp tank: The Shrimp Doctor’s Way
Many articles online has claimed that CO2 supplementation in shrimp tanks re**rd shrimp growth rate and decreases survival rates of juveniles. In The Shrimp Doctor’s MOST HUMBLE opinion, this is not true!
The Shrimp Doctor has had excellent survival rates of both adults and juveniles. In fact, we feel that the frequency of females getting pregnant seems far more often in a planted shrimp aquarium. All of our planted shrimp tanks are supplemented with CO2. So what is the key to master this challenging problem?
There are actually two keys to this problem; Patience (yes, again) and observation.
The Shrimp Doctor does not use drop checkers in our tanks. This is because we believe the best indications of CO2 are the organisms, shrimps and plants, in our tanks. Furthermore, The Shrimp Doctor feels that the target level of 30ppm of CO2 as indicated by a drop checker is slightly too much for a planted shrimp tank.
First, always remember to start off slow. What we mean by starting off slow is to initially have a slower rate of CO2 being injected; say 1 bubble per second. Continue to observe the shrimps’ activity level during this time. Slowly increase the rate of CO2 injection daily and continue to observe the shrimps after each increase. The increase in CO2 injection should be done during a time of photoperiod so that the plants will be able to utilise the increased CO2 during photosynthesis. It would be useful for those just starting off to use a drop checker concurrently to monitor the levels of CO2.
The Shrimp Doctor recommends that the level of CO2 in a planted shrimp tank to be slightly lower than the ‘optimum’ level of 30ppm. Keep in mind that CO2 injection is not absolutely needed for plant growth; it is only used as a supplement. Therefore it is perfectly OK to ‘underdose’ the amount of CO2 in a planted shrimp tank (this prevents accidental overdosing and killing all your shirmps!)
If anyone has any questions, feel free to PM us or leave a comment. Also feel free to share some of your experiences with us.
