Replacing rock, worried about phosphate

[Hans24hrs]

I have been having an ongoing problem with high phosphates in my tank(s). I tested everything I could think that would cause it and narrowed it down to my rocks. Also I have the same rock in three tanks, one of which was a QT tank that just has a large rock from display with Zoa's on it. All three tanks have high phosphate issue. So I decided to replace rock in main display with real reef rock. I currently have rock in holding tank and it has been fully seeded and cycled.

So here is my big question. Do I replace all the rock in main display at one time or do a 50/50 swap. The manufacturer said to do 50/50, but that was adding it as dry rock. My dilemma is if I do 50/50 do I run the risk of the new rock absorbing phosphate. If I add all at once is it possible that I get some kind of ammonia spike. I have lost most of my SPS and I am going to move what's left of the coral to holding tank, but I can't move fish (to big, to many)


I posted on another site, just would like as much feedback as possible.
Thank you in advance,
Hans

 

[Kungpaoshizi]

Get some lanthanum chloride and nopox. If you're serious about it, get some calcium nitrate and dosers for the nopox and CN.
Calcium carbonate sucks up and releases phosphate, it's an on-going cycle. 8.3 is max absorption, as you move away from there, it releases faster to find equilibrium with the water.

 

[Hans24hrs]

I will keep those in mind. But I am hoping with the removal of the current rock that will help eliminate the high levels

 

[Randy Holmes-Farley]

I have been having an ongoing problem with high phosphates in my tank(s). I tested everything I could think that would cause it and narrowed it down to my rocks. Also I have the same rock in three tanks, one of which was a QT tank that just has a large rock from display with Zoa's on it. All three tanks have high phosphate issue. So I decided to replace rock in main display with real reef rock. I currently have rock in holding tank and it has been fully seeded and cycled.

So here is my big question. Do I replace all the rock in main display at one time or do a 50/50 swap. The manufacturer said to do 50/50, but that was adding it as dry rock. My dilemma is if I do 50/50 do I run the risk of the new rock absorbing phosphate. If I add all at once is it possible that I get some kind of ammonia spike. I have lost most of my SPS and I am going to move what's left of the coral to holding tank, but I can't move fish (to big, to many)


I posted on another site, just would like as much feedback as possible.
Thank you in advance,
Hans

I agree those are both reasonable concerns. I'd personally replace it 50/50.

 

[Hans24hrs]

How long would you recommend waiting before adding the second batch of rock.