Reply. Hello Sterling. Thank you for your comments and the
beautiful aquarium pictures.
I'm glad you decided to get a Penguin 170, which is a filter that we recommend for a 29-gallon aquarium like yours. We recommend you change 20% of the water twice a week, not
just once a week. The Neon Tetras are good fish for a 29-gallon aquarium.
It's good that you have only one Red Tail Shark (RTS), because we say keep one RTS or many RTS but not just a few RTS. However, a RTS is usually not a good tank mate for Neon
Tetras. It surprises me that the RTS has not bothered your Neons. Maybe it will, when it gets a little bigger.
Soon your RTS, Discus, and Plecostomus will need a bigger aquarium with at least 50 gallons of water. As you have discovered your Discus will do well in water with a pH of 7.5.
We have kept many Discus in water with a pH of 7.8 and even higher, and the Discus usually do very well in this water, but they will rarely breed in water with a high pH. If
they do breed, their eggs will rarely hatch.
Good luck with your aquarium, and thanks again for sending a picture of your aquarium.