I assume by 'algea-like', you actually mean cyanobacteria. The problem is that anything that uses photosynthesis creates oxygen, and oxygen eventually depletes the planet's chemical oxygen sinks, which inevitably leads to a Great Oxygenation Event. The latter provides a new powerful source of energy for life, which then leads to something like a cambrian explosion.

The largest uncertainty in these steps is the timeline for oxygenation to deplete the planet's oxygen sinks. This is basically the time it takes cyanobacteria to 'terraform' the planet. It took 200 million years on Earth, but this is presumably dependent on planetary chemical composition and size.

From the known exoplanets, we can already estimate there are on the order a billion-ish earth-size worlds in habitable zones. By the mediocrity principle, it's a priori unlikely that earth's chemistry is 1 in a billion. Especially given that Mar's composition is vaguely similar enough that it was probably an 'almost earth'.