DIY CO2 is very easy. All you need is a limewood diffuser, some kind of tubing, 2 cups sugar, and 1/8 tsp yeast... and a 2L bottle. Force the tube into the lid and add the sugar+ yeast, seal it with silicon/plastacine and shove it into an obscure corner. VOILA! done. In that high of light you will probably need CO2 for your blyxa. Do this if your BF doesn't want to share. Total cost is about $8 initially (assuming you have a bottle and tubing) plus the price of 2 cups sugar for each additional 3 weeks. You might want to use a smaller bottle, like 591 ml or 710 ml... or 1 L
Good luck! It is already better than either of my tanks.
My tank sucks now
Fraternity of Dirt # 22