Hi Jayy
First I'd like to know a couple of things about your project:
1) If you sampling1,800 different sensors sensors,
How are you reading all of them using only 30 ADC channels?
How are you multiplexing the signals?
2) If you are indeed multiplexing the signals you must take into consideration there will be a delay between readings,
slowing down the total mount of time necessary to perform the readings and conversions
3 If you are reading 1,800 consecutive samples instead of reading 1,800 different signals you can easily get the
conversion time you are looking for, please ellaborate, your statement is not clear enough.