Science Buddies: "Ask an Expert"

Hello! I am currently a Grade 10 Student situated in Canada, and I have a few inquiries regarding a borax-water solution as a means to reduce cyanobacteria concentrations? I want to ask if Borax raises pH, since I heard somewhere that it does (I'm attempting to reduce the alkalinity in my science fair experiment since blue-green algae can raise pH). Furthermore, how much borax and how much water should I mix to add to 10mL of algae (Spirulina) culture? A response as soon as possible would be great, and extra information is gladly accepted. Thanks!

I just got my culturing kit for Arthrospira Platensis (Spirulina) and I need to use the 2ml of Arthrospira to increase to 50ml. How long will this take? I also have nutrients/salts.



Moderator note: I've combined your two posts so that the experts monitoring this forum will see both of your posts and will also be able to see that no one has responded. Thank you for your patience!

I also see online that borax will raise the pH to about 9.5. the amount you add to your culture depends on what you want the final pH to be. To calculate that you would need to find out how much the bacteria change the pH. That sounds hard to find, so maybe the best idea is to do the experiment yourself!
If your experiment is already how does borax effect bacterial growth, you should just add different amounts of borax to the same amount of bacterial solution. Checking the pH (pH test strips are much cheaper than a pH meter if you don't have access to one) of each solution will also be important data for your results but also to answer your questions here about the relationship between borax and pH