YASAM - Potted Carpeting Plants Micranthemum aka Monte Carlo (SG STORE Live Aquatic Plant)

HC refers to Hemianthus callitrichoides 'Cuba', sometimes called Dwarf Baby Tears.

MC refers to Micranthemum 'Monte Carlo'.

HC has the smallest oval leaves of the aquatic carpets, about the size of duckweed.
MC is quite a bit larger when grown under robust growth parameters.
At maximum size, MC leaves are about 3 to 4 times larger than HC. However, under lean and overcrowded conditions, MC can be very similar in size to HC.

Monte Carlo is very hardy. It will grow on wood or rock without substrate, and will even grow in tanks without CO2 injection if given enough light and time.

In comparison, HC needs high CO2 levels to grow well and needs soil substrate to grow well. While MC tolerates overcrowding quite well, the bottom layers of HC deteriorate very quickly once overcrowded.

In short, while MC is a really hardy carpet, HC is, by comparison, extremely picky.

The two may look similar, but are miles apart in the care and conditions required to grow them well over time.

Maintenance:

Both MC and HC require pruning (in a CO2 injected tank with strong light, every 2 weeks if not 3) to stay in good shape. With MC you can get away with pruning less frequently, while HC requires a much (repeat much) higher level of discipline and regularity.

What happens if we do not prune? The top layers shade the lower layers, which begin to deteriorate, as shown in the picture above. In MC this process is more gradual. With HC it happens much faster. You cannot replace regular pruning with better or more nutrition/fertilization;

As a general rule, prune earlier and earlier rather than later. It is far better to prune aggressively than leniently.

As the bottom layer deteriorates, you need to replant healthy parts of the top layer.