Hello,
I can only offer suggestion about your A. cuprea. I have quite a few and all are doing great. I'm in the tropics and mine get watered every day.They are in an aroid/anthurium shadehouse. They are potted in an extremely well draining mix which includes 40-50% of what we call qwincan I think you call it cinders. They put it on the roads in the U.S. for traction when there is ice on the road. Everyone I know who grows it successfully waters often and uses a very well drained medium.
Regards,
Brendon

Neither of those are true aquatic species. They like a lot of water but not to stand in water. I grow mine in the ground in pure sand (because that is what the soil in my yard is) it drains like a sieve so I water every day.

Thanks!

I have them both in "self-watering" pots (pots with a reservoir at the bottom -- the dirt does NOT sit in the water, it has a system to wick water into the dirt), in good potting soil with extra perlite plus extra moisture crystals. I've been meaning to repot with either extra bark or something else added to improve drainage even further, but I haven't gotten around to it.

So far the cuprea looks fine. Some of the amazonica leaves are brown at the edges. Any ideas?

I grow amazonica-type hybrids in pots as houseplants as well as in the yard and greenhouse. The ones I grow in the house are huge old plants, multi-trunked specimen plants. I have a loweii that is almost 10 years old. The others are Polly and Purple Prince. I water these all ONCE A WEEK. That's all. I totally saturate the soil ONCE A WEEK. They grow under a bank of skylights in what amounts to full sun for about 8 hours daily. Brown edges on yours could be either too much moisture at the root level, or humidity too low.