I have two, and keep just under a cup of each in the fridge, in jars.

The night before making bread, I dump a cup of water into the jar,
mix, pour into a plastic bowl, and beat with an egg whisk. I then mix
in two cups of flour, using a stick. I then put the bowl into the
microwave (switched off), and leave it till next day.

Next day I mix it to get the gas out, and replace what I took out of
the jar. The rest I use to make bread.

I leave the jar on top of the fridge, until it doubles, then put it
back into the fridge.

Starter one bubbles a bit, then settles down.

Starter two climbs almost to the top of the jar. I have to use a spoon
to get the air out. I have to use the spoon twice, once again later
that day
Yesterday I forgot and it climbed right out of the jar, knocking the
top off, and spread across the panel in the fridge. I calculate that
sextuplicated (? x6) . And that after I had knocked it down once.

Do I have an abnormal starter ? I make bread with it about once a
week. The bread is not very sour, and has a lovely texture. Starter
number one makes rather a flat, sour bread, which is also nice,
totally different from number two.

If I DO have an unusual starter, anyone coming to Brazil is welcome to
a sample.

FWIW