You currently have Angels you want breed, but you also want to get started with discus - correct ?
Many discus-keepers successfully keep them with Angels, but the majority that do so have some reasonable level of experience with both Discus and Angels.
For a newcomer to discus, however, this can be problematic. Occasionally, Angels will contaminate discus with harmful pathogens that they are resistant to, but the discus are not. A larger, more common problem is there can be compatability issues (both being Cichlids) and at times Angels can prove to be more aggressive, and out-compete discus for food, thus stressing the discus (this depends on sizes of both types as well).
Having said that, it can be done without problems, but my suggestion would be that, if you want to get started with discus and the following is doable for you - keep the two types separately in 2 tanks, at least for a few months until you get some experience with the discus, and become quite familiar with their traits and behavior, as well as letting them become comfortable in their new surroundings.
Once you're comfortable with that, you could introduce the 2 together in a suitably sized tank, keeping in mind as others have said, that you need to start off with at least 5 discus, and you already likely have several Angels if you're intent on breeding them.
That's my best advice to you, as a safe approach to successfully keeping discus and angels together.
Oh, and you don't need to mess with your pH - what you have would be ok for discus without alteration.
