Phosphate Management

[ptreef]

Update: I decided all the previous GFO was exhausted so I added 3 more cups. I have been testing alk frequently with my phosphate due to initial drop in dkh as phosphate dropped. As of today, alk is back to 8.1dkh and phosphate to 0.10. I’m hoping that things start looking better soon as I’ve seen more of the Sps colonies start to show “burnt” tips or patches of STN/RTN

 

[ptreef]

Today I took the GFO reactor offline. My phosphates even after 100g water change remain 0.10-0.14, and most of my Sps are suffering much worse than when the phosphate was high. I’m hoping they can recover now

 

[Adam]

SPS does not like fast drops in PO4. The alk consumption went up as the PO4 dropped because the coral started growing faster. Burnt tips is usually a sign the the skeleton is growing faster than the tissue can cover it. Throughout this thread I haven't seen you post the nitrate level. That is just as important.

What do you feed the fish and do you feed the coral? Please post that info and your NO3 level.

 

[Adam]

Also, a 100g water change will do virtually nothing to help with managing PO4. 100g is 12.5% of 800g. So use a multiplier of 0.875 to see the result of a water change.

A po4 of 0.15 x 0.875 = 0.131. Like is said virtually no change.
Stacking 100g changes one after another with not help either. 0.131 x 0.875 = 0.115 x 0.875 = 0.10.

Personally I'd keep running the gfo to maintain the level your at and lower the light intensity 15-20%. The tips should get covered in time.
Then test the no3 and send out an icp to get a good baseline of where everything else is.

Your still welcome to stop by

 

[ptreef]

I haven’t checked nitrate but I’ve looked into the Hannah high range checker. I’m not sure 100% if burnt tips is the right description vs stn. Mostly on the tips and receding tissue.