I'm in the process of setting up my 150 gal tank. Looks like my funds wont
stretch to a presurised CO2 setup so i am wondering if DIY soda bottle/yeast
CO2 systems can work with a tank this size?

I plan to use a powerhead into a gravel vac with bioballs/sponge to disolve
the CO2 so it should be pretty efficient at using what CO2 I get.

How many 2l bottles would I need?

Thanks