Submerisble Water Pump Question

Wondering if a submerisble water pump will heat up the water in a nft or dft system if it runs continously with no resistance? Is a chiller nice to have or a necessity?

Thanks!

The thermal mass of the water against your pump will keep your pump cool as a cucumber.

I agree, the water will do a better job of cooling the pump than the pump heating the water as long as the res isn't really small. With NFT it should be running 1 min on and 4-5 off or something like that so it's even less of an issue.