Hiatt filtration system

[CaptainGreg]

I'm doing research on Hiatt system and I was reading through this thread. Why do you think that the pH rock is junk? Also, I want to set up a Nano with Hiatt. Do you guys think it's really necessary to have the outflow above water? Has anyone have success running outflow underwater?

The water flowing out of the filter does not have low enough PH to desolve it. It is a type of marble and it take PH less than seven to desolve it. The gravel was too expensive and it require more pump power to have it go through gravel container.

I use the Sea lab block to supplement cal and other trace element.

I do not have the out put above the water. I have it under the water, but make sure you have enough surface water egitation for air exchange.