Solving problems with the research

Doing our research we have encountered several problems. The CO2 tank was used up completely by the first 3 days, so we needed to come up with another type of agitation since buying CO2 tanks are expensive.
We have purchased one is coming soon, but it will only be use for 2 cultures for now on. As our project we need to find out if CO2 is beneficial to algae growth so we have 2 cultures with CO2 and 2 without, we are measuring the cell growth and after 17 days determine which is better. Since the algae were left without agitation for some time, we plan to start over again with the 2 cultures that need CO2 while the other 2 (Non CO2) that are in the Shaker we will continue to monitor them and post there progress.

We also want to determine the best Nitrogen Concentration and Nitrogen deprivation period we use Urea as our Nitrogen source, for this experiments we have 15 cultures divided into 3 groups of 5 cultures:

1. Group 1 (green) has an Urea concentration of 1.2g/L
2. Group 2(red) has an Urea concentration of 1.8g/L
3. Group 3(blue) has and Urea concentration of 2.4g/L

For them we have been measuring there pH and cell growth daily and we will also measure there Urea consumption using an Spectrophotometer.

The problem that arise is that we were using CO2 as a source of agitation so when the tank ended they concentrated at the bottom and have not grown as we expected. We are going to start over with them too. We will use Air for a source of agitation. Another problem we identified is that the Nutrients we feed had a very acidic pH(~3). To regulate a pH at ~6.8 we have a new culture that we are investigating now for this one we pour in the nutrients of a 3 pH and use NaOH 0.1M and added it until the pH was ~6.8 then we poured in the algae its source of agitation is Air and we are measuring its pH and cell count each day.

If they grow successfully, we want to regulate the pH of all the 15 cultures once we start up again with them.

Stock Culture Non CO2 With CO2