I didn't know that Angels do well on a 7.6 PH. If you decide to change the PH, do it slowly like a 0.2 every 48 hours. Take your time don't rush it. I use Seachem Acid buffer and Seachem Alkaline buffer (2 parts Alkaline to 1 part acid to reach PH = 7. The ratio depends on the water hardness. The harder the water, the more acid you need to lower PH. I soften my water using Tank soft to an in between soft and hard range). In your case, just add a little bit of acid buffer and check the PH after 15 minutes to get an idea of what is required to lower PH by 0.2. If you decide to soften your aquarium water, you can use Tank Soft just enough to lower a few degrees of total hardness without changing PH by more than 0.2 at a time. Avoid using Acid and Tank Soft simultaneously in the tank because the softer less acid is needed to lower PH and softning the water does lower PH too.
If the Dwarf Gourami is slow, maybe it is O.K. to leave it in the aquarium. Once the Angels decide to spawn, they will confine the other fish in the tank to a small section on the opposite side where they lay their eggs. (The best is to leave the parents alone with the eggs since the other fish will eventually eat the fry). I also understand that first time egg layer parents can eat the fry. Feed them lot's of fresh protein (frozen bacteria free brine shrimp and Krill).
If they lay eggs, have you decided what are you going to do? Transfer the eggs to a little egg hatcher tank or leave them in the aquarium with their parents?. (If you leave them with the parents, make sure the fry can't get sucked by the filter. Perhaps put a sponge on the In take tube of the filter to avoid lthe fry getting sucked and killed by the filter suction.
Good luck
*celebrate
