Edit: I think you mean Algae (which is EPA) Edit2: My mistake, I read Algal as ALA rather than Algae (algal)
The cultivated strains have been selected and/or genetically engineered to have enhanced production of certain long-chain omega-3 fatty acids.
The composition of an "algal" oil ("algal" is the adjective derived from "alga", "algae" is the plural of "alga") depends on the particular strain that the vendor has used in production.
The first cultivated strains produced only DHA, but in recent years most vendors use strains that allow them to sell oil that has a mixture 2:1 of DHA and EPA, with minor quantities of other long-chain omega-3 fatty acids.
For growing it would be difficult to obtain a good strain. The strains used by commercial producers were originally isolated from some mangrove forests or other such places on sea shores, but then they have passed through years of selection and/or gene manipulation. Even when a good strain would be available, a culture that is grown in less controlled conditions could be susceptible to being wiped out by a disease, I have no idea.
In any case, I think the difficulty is in the oil extraction, not in the culture. In industrial conditions the extraction could be made with supercritical carbon dioxide, for maximum cleanness of the extracted oil, but that would not be feasible at home. Using an organic solvent, like hexane, might be possible at home, but that would be dangerous and there is the risk of contamination of the edible oil with solvent residues.
Accurate chemical analysis of the oil would be needed, to determine the fatty acid profile and validate the extraction method.
But these results seem to say at higher concentrations ALA lowers risk of EOD. Which tends to refute the belief that only DHA/EPA lower chronic inflammation or that EOD is not just a story about inflammation.
The abstract only partitions the omega-3 acids in DHA and non-DHA.
While non-DHA includes ALA, without any concrete evidence that ALA has some direct role, it is more likely that the correlation seen with non-DHA refers not to ALA, but to the other long-chain omega-3 fatty acids besides DHA.
Humans can elongate ALA into useful long-chain acids, but the efficiency of this is typically lower in males than in females and lower in old people than in young people. Usually pregnant women have the best conversion efficiency.
Unless you monitor your blood composition, you cannot know if eating ALA (e.g. flax seeds or oil, or walnuts) can be sufficient for you. If you are an older male, it is very likely that eating ALA cannot be enough for avoiding deficiency.