Wont be needed - I thought I'd need one too since I installed on a concrete floor up north

water temps stay in the high 60's and low 70's

floor is in the 40's

If you do happen to need one (water below 50) I've got 4 spares never been opened.

Oh, and why.... the air pump pulls room temp air, and blends it in with the water
low_rdr Reviewed by low_rdr on . rdwc question im considering setting up a small rdwc grow to see if it makes things easier for me since soil is being problematic. I understand the idea behind it, but i need to be able to see it in my mind to be able to build it. I have quik and crappy drawing i made that should explain what i want it to do and that is maybe just how it works in the first place but im not sure. on rdwc systems do they just constantly drip or spray the roots drawing from a pool at the bottom of their bucket or do you use Rating: 5