EPA and DHA are found in the same algae. The younger you harvest the algae, the more EPA.

First of all please note that every individual responds differently to Omega-3 intake.

Testa EPA + DHA is a complete Omega-3 product that is suitable for everyone. With 1 capsule per day, one tackles the perfect support for heart, brain and eyes. Testa DHA + EPA contains at least 450 mg Omega-3, and more than 250 mg DHA and 125 mg EPA per capsule. It is especially beneficial for vegans and vegetarians. 

EPA and DHA mostly do different things. If your goal is reducing cellular inflammation, then you probably need more EPA. People who need to recover from depression, ADHD, brain trauma, etc. are advised to maintain high levels of EPA in the blood.

Testa DHA is suitable for people who like to have only DHA Omega-3 fatty acids or people who especially take the Omega-3 for eye- and brain health. Testa DHA contains over 250 mg Omega-3 in the form of DHA. It is an ideal supplement for pregnant women in combination with Testa EPA + DHA, because of the additional benefits that this combination offers for the fetus or infant.

DHA does a great job of making membranes (especially those in the brain) a lot more fluid than EPA does. This increase in membrane fluidity is critical for synaptic vesicles and the retina of the eye. Nonetheless you always cover your bets with Omega-3 fatty acids by using both EPA and DHA at the same time.

More info can be found here: What health claims may Testa Omega-3 EPA + DHA make?