Dosing KNO3

[JamieC]

OK, some sort of new chemistry is happening in my tank. It is 3 months old and doing great (except for an assassin Dottyback). Despite how much I feed, can't get nitrate above zero. I thought maybe my Salifert test kit was broken. I bought some KNO3, made a liter solution, and dosed a sample gallon of water. Tested it, and what do you know, the kit works. Soo...as I am deathly afraid of getting Dinos from a low nutrient tank, I slowly dosed the KNO3 to my tank and brought the Nitrate up to approximately 5 ppm.

Since I did this (2 days ago) all of my live rock has very actively been producing a carpet of fine microbubbles. At first I thought it was the start of a dino outbreak and I was beside myself...but it's not Dinos. It's similar to a freshwater planted tank that is "pearling". The little micro bubbles just release from the rocks and escape the tank as a gas. What the heck is this? Nitrogen gas? Oxygen? What is happening?

 

[Randy Holmes-Farley]

My guess is oxygen from increased algae, even if it is hard to see. Does it change with the light cycle?

 

[JamieC]

Bubbles hang out on the rock at night but don't release free. It definitely resembles oxygen production from plant photosynthesis. I just expected an obvious plant formation/algae to be visible. I've only had film type of green algae on the glass and rocks to this point. Nothing that has "leaf-like" structures. I can blow the bubbles off with a baster and they come right back in a couple minutes.

 

[Randy Holmes-Farley]

Bubbles hang out on the rock at night but don't release free. It definitely resembles oxygen production from plant photosynthesis. I just expected an obvious plant formation/algae to be visible. I've only had film type of green algae on the glass and rocks to this point. Nothing that has "leaf-like" structures. I can blow the bubbles off with a baster and they come right back in a couple minutes.

The may be coming from O2 created elsewhere in the system.

 

[JamieC]

Ok...so my rock is definitely getting darker in color...and while I don't see a massive "nuisance" outbreak, the coloration on the rock is green in nature. As such, I definitely agree the bubbles are a result of photosynthesis. My pH has gone up from a high of 8.1 to a high of 8.3. I'm assuming this is a result of the algae processing CO2.