Rowaphos and RTN

[spyro]

Randy,

Over in the SPS forum, some people have been reporting some ill effects due to the sudden use of RowaPhos in their reef tanks. Specifically, some are claiming that there SPS corals have aquired RTN after sudden introduction of RowaPhos (Ferric Oxide Hydroxide) as a filter media to reduce phosphate.

People have been speculating that it is not the RowaPhos itrself that is causing problems but the results that it achieves. That is, lowering phosphates from as high as .1 to .015 or lower in a very short amount of time (days). I began using it and lowered my phosphates from .1 to undetectable in less than a week's time. I have not had any problems with RTN....just all good things like improved water clarity and almost complete elimination of the algae bloom in my frag tank, connected to my display tank.

My questions are:

1. Is there any theoretical basis that supports the idea that the media itself can cause problems with SPS corals ?

2. Could lowering phosphates quickly be enough to stress SPS corals to the point where they aquire RTN ? Up to now I thought lowering PO4 was a good thing, but the findings of a few SPS keepers suggests that lowering P04 too quickly could cause problems.


Thanks !
Chuck Spyropulos

[cecilturtle]

Tagging along. I had a small frag Humilus along with a Cap that has RTN'd on me. Both have been doing well and have been with me more than a year. This about 3 weeks after switching to RowaPhos. Coincidentaly, the macro in my refuge has starved out too.

Testing with a Sera Phosphate kit results in less than 0.1 mg/l

The RowaPhos is run through a HOT Magnum. Previously to Rowa I have been using PhosBan for app 4 months so I don't think my case was drastic but anyway......

[Randy Holmes-Farley]

I don't know why reducing the phosphate would cause RTN, but these systems are complicated, and I suppose it is possible. It may well shift the populations of various algae and bacterial species that predominate, and perhaps that could do something.

Could it be acting directly on th coral? Maybe. The relative growth of the coral and the zoox might also shift on reducing phosphate.

[garyfish]

what is rtn? any way to correct it?

[Randy Holmes-Farley]

RTN is Rapid Tissue Necrosis. It is a disease, or at least a condition where certain corals, especialy SPS corals, rapidly loose tissue and die (within hours to a day or two).

I've never experienced it, so I've not paid too much attention to what to do if it happens (if anything really works). I'd suggest searching on RTN.

[cecilturtle]

The humilus has completely gone. I had found one more that was starting to RTN but seems to have ceased along with my cap which has been making a nice recovery since taking my Rowa out. I had suspected the Rowa because nothing has been intro'd for quite some time and no parems have been altered except for the change in media in my canister from PhosBan to Rowa, but I was hesitant to take it out in lieu of all the positive reviews here. The only thing different as I can tell is I run a canister (250gph) vs the reactor.

Interestingly enough, since taking the Rowa out, I found my first spot of cyano in my macro (Chetamorpha). Although I have never had a problem with it, it has been a nuisance, even with Phosban.
Oh well, tis the season for dieting.....

[Gary Majchrzak]

cecilturtle- Did you fill the canister filter with the same amount of Rowa as you did Phosban?

[cecilturtle]

Near as I can tell Gary, it was less media. I used the HOT Magnum without the media chamber. Placed the second smallest box of ROWAph with bag and an additional bag of Black Diamond in the canister, basically creating a circle. The canister would come off for app. 4 hours after feeding so I would reduce the amount of buildup on the media bags.

There's no denying this product worked great in removing phosphate, but I do not have several pieces of equipment such as an ORP meter or a constant PH monitor so I am skeptical in my execution of this product. Is it the amount? Or the flow? Was I borderline problematic with phosphate (having a 2 year old DSB)? Or was I low on ALK (9.6)? Either way, I'm tagging along in hope that some common ground will flag up.

[spyro]

Well, I regret to report that a few of my SPS corals are bleaching. At first I though it must be the Rowa, but I measured my alk and it was 6 !!!!! (usually 9-10). I then found that my calcium reactor was not putting out any effluent.

I now believe it was not the Rowa since I had been using it for a month with no ill effects. I think the low alk is what has caused the bleaching. I added buffer over the last few days and also fixed the clogged Calcium reactor. I am trying to keep everything as stable as I can (ph, alk, temp) and I am not giving up on the Rowa yet....it really works well at lowering phosphate.

[Randy Holmes-Farley]

That sounds like a reasonable conclusion. Hopefully the corals will come back OK. :)

[Andrewsreef]

Just for the record, I am using the Salifert brand of phosphate remover, Phosphate Killer and I am not having any negative effects on my SPS or any other corals. May actually be helping slightly with my colors but not sure yet. I a have been using it for a month now.

Thanks

Andrew