Its not that you can't keep red plants alive it is more due to low to moderate light that can cause the red to fade. Using higher light and injecting CO2 is generally needed to keep reds, purple colored plants that color. With that said, it hard to tell by the pic but in person the tank have a lot more color contrast-the Crypts are a dark bronze color and the Rotala has a pink and gold hue and all different shade of green.
Since these are mature natural planted soil based tanks-they don't need water changes the way non-soil tanks or tanks with or without plants. The soil is alive and then along with the active plant growth-then with the fish, snails and shrimp...Make the soil based NPT as near a complete ecosystem that can be created in a closed system. Everything has a job of sorts....Its a balance.....
Water changes on the large tanks-are 3-4 times a year at most. The 10gal and under do not have filters and are used for spawning so they get more water changes than are needed-water changes are done for fry growth. The 1-3gal tanks get maybe 6 water changes a year-this depends on what I am doing with them.
Since all my tanks are open top for better light penetration to plants-I do have to top off with water on a weekly basis.
Proper lights, color temp, age of bulbs, photoperiod, light penetration are the driving force behind successful planted tanks-without the proper color temp the plants can't photosynthesize.
I don't add any ferts or inject CO2-the tank creates all this on its own from the byproducts produced by the livestock and decomp.
Najas indica (naja grass)
C. piauhyensis (red)
Vallisneria americana-var Biwanesis
V. gigntea (get over 5ft)
Echinodorus bleheri (amazon sword)
E. tenellus (chain sword)
Hygrophila dfformis (westeria)
H. corymbosa (giant hygro)
H, siamensis (thin leaf)
Nymphaes stellata (red lily)
Microsorium pteropus (java fern)
Pistia stratiotes (water lettuce)
Limnobium laevigatum (frogbit)
Lemna minor (duckweed)
Vesicularia dubyana (java moss)