Dosing phosphate causing leaching live rock?

[rynosreef]

I was looking over my numbers and noticed something worth mentioning. I usually have a daily pH swing of 8.05 to 8.28 or so. This is with the skimmer pulling air through a CO2 scrubber. The day after I mounted these frags we went on a 3 day trip. When we came home, the pH read 8.68/Alk 7.6. Alk is usually 8. It's hard to believe the pH could be that high, but in a house with no one adding CO2 and a scrubber... maybe?

Does it seems likely that the combination of
A) frags being stressed from handling, mounting and
B) this pH spike, could be the cause of the onset of STN?

 

[Randy Holmes-Farley Verified Community Expert]

I was looking over my numbers and noticed something worth mentioning. I usually have a daily pH swing of 8.05 to 8.28 or so. This is with the skimmer pulling air through a CO2 scrubber. The day after I mounted these frags we went on a 3 day trip. When we came home, the pH read 8.68/Alk 7.6. Alk is usually 8. It's hard to believe the pH could be that high, but in a house with no one adding CO2 and a scrubber... maybe?

Does it seems likely that the combination of
A) frags being stressed from handling, mounting and
B) this pH spike, could be the cause of the onset of STN?

If it really got that high, it implies you have inadequate aeration. Complete aeration with normal CO2 air would need an alk way over 15 dKH. I'm suspicious that it could get that high without initiating some precipitation of calcium carbonate.

Regardless, I'm not sure if that pH is stressful for corals or not.

 

[Graffiti Spot]

I have had ph fluctuations from adding a co2 scrubber burn acropora. And it only jumped up maybe .3 or so. So I can imagine the jump from you leaving the house could have caused issues if test results are right.

 

[Reefahholic]

Because some folks have excessively low phosphate and run a risk of dinos.

Exactly.

In some systems the rock and sand can aggressively bind the available PO4. This can kill the corals. Acropora will need some PO4 especially in a new system or they will check out on you.