Effectiveness of Dosing Probiotics to Water

[Randy Holmes-Farley]

But how comes then that many people now add nitrate to get more colors on their corals? So better colors with less nitrate or with nitrate in a 5-20 range?

Color is a very complicated issue, IMO, and made far more complicated by the fact that people are rarely talking about just one organism under one type of lighting. Different people also like different looks.

The best I can gather from reading so many experiences is that coloration does frequently relate to N and P levels, and more often than not, reefers seem to think their tanks look best at a middle ground of nutrient levels, neither too high nor too low.

 

[Hans-Werner]

But how comes then that many people now add nitrate to get more colors on their corals? So better colors with less nitrate or with nitrate in a 5-20 range?

Nitrate is a strong oxidant and may cause oxidative stress that may bleach zooxanthellae. The oxidant may also lower availability of other nutrients like iron and phosphate and in this way make "more colors".

I have no good experiences with nitrate dosing and finally the advocates of nitrate dosing should better be able to explain the positive effects of nitrate. I can only explain the negative effects of nitrate which include bleaching by ROS and burning of light exposed coral parts. I have seen these effects and try to avoid them.