Actually their metabolism is linked to their tank temperature so if you have higher temperatures you have a shorter life span for your shrimp but the juvies grow more rapidly and as your going to sell some of them on a higher temp of around 26C would be better. At those temps you will also need some live plants to keep the oxygen levels high. They are not cold water they are sub tropical like the majority of shrimp they can be kept as low as 10C or as high as 30C but you elongate their lives and slow their movements at colder temperatures and its like giving them caffeine when at higher temps. The diurnal temp fluctuation in the tank if no heater is provided would cause big problems for these shrimp. I am not sure about your house but mine gets cold around 1 am as there is no heating and relatively boiling at 1pm.
Something like this would be good planting for them
http/farm1.static.flickr.com/225/5227308...415a7ee.jpg?v=0
Something like this would be good planting for them
http/farm1.static.flickr.com/225/5227308...415a7ee.jpg?v=0