maintain at

maintain (something) at (something)

To keep something at a particular setting or level. I try to maintain my savings at $1,000, at least, in case of emergencies.
See also: maintain

maintain something at something

to keep something at a certain level, setting, degree, amount, etc. You must maintain the temperature at 30 degrees Celsius. We have to maintain the temperature at a very high level.
See also: maintain