I am an undergraduate, and I need some help on what statistical test to conduct for a research project I am doing. I am fairly new to statistical tests (only took AP Statistics in High school), and the resources my advisor has pointed me towards didn't seem to have anything that worked, so any help pointing me in the right direction would be highly appreciated.

My study attempts to test the comparative effects of the presence of photosynthetic organisms macrophytes and algae on the growth of E. Coli. To do this, we are introducing algae and macrophytes into vials of a growth medium as shown in the picture attached here.

Because we don't know the relative proportions of algae and macrophytes in the environment, we came up with a system to create multiple blocks with different proportions of algae and macrophytes in order to randomize the proportions. Thus, if one photosynthetic organism leads to an increased number of bacterial growth in the majority of the five blocks, we know that that particular photosynthetic organism leads to more bacterial growth, regardless of the proportion of macrophytes to algae in the environment. For example, as you can see in the figure, the first block has two vials with only macrophytes in one and only algae in the other at a proportion of 1 macrophyte to 5 algae. Then in the vial with combined algae and macrophytes, we retain those proportions when we combine (i.e. there is a mixture of 1 part macrophyte to 5 parts algae in the same vial). We then switch the proportions in each subsequent block — for example, the second block has a vial with only 2 parts macrophyte, a vial with only 4 parts algae, and a vial with a mixture of the 2 parts macrophyte and 4 parts algae.

The trouble is, we aren't able to figure out what statistical test to conduct for this study design we came up with. We were thinking a 2 part ANCOVA could work but weren't sure? Any help on what statistical test we could conduct to verify our results, or if you have any idea on how we can modify our study system to control for the unknown proportions of algae and macrophytes in the environment without doing it in this block system would be very helpful!

Thanks a lot!