Phosphate supplement congealed in end of dosing tube

[ceaver]

Just noticed this very strange occurrence at the end of my phosphate dosing tube, which is held in place along with 3 other tubes by a standard holder. I'm dosing Seachem Flourish Phosphorus. There was a stringy, snotty looking thing hanging out the end of the tube down to the water surface. I tried to pull it out with a piece of paper towel to no avail. So I grabbed a shot glass and turned on that dosing pump and out came this:

Any ideas what may have happened here? If the water level of the sump (which is the back section of an all-in-one) touched the bottom of the dosing tube could it cause the P supplement to do something weird like this?

 

[Randy Holmes-Farley]

Just noticed this very strange occurrence at the end of my phosphate dosing tube, which is held in place along with 3 other tubes by a standard holder. I'm dosing Seachem Flourish Phosphorus. There was a stringy, snotty looking thing hanging out the end of the tube down to the water surface. I tried to pull it out with a piece of paper towel to no avail. So I grabbed a shot glass and turned on that dosing pump and out came this:

Any ideas what may have happened here? If the water level of the sump (which is the back section of an all-in-one) touched the bottom of the dosing tube could it cause the P supplement to do something weird like this?

Might be magnesium hydroxide and/or calcium and magnesium phosphate, all of which can form from high pH phosphate additives and seawater.