Kalk, reactor reverse cycle

[tankslave]

Hey Randy,

I've been thinkin about switching over to a reactor to feed my system and have been doing some reading about the aditional benifits of a reactor. My only concern is that the reactor will lower my pH and hence inhibit coral growth. As it is my kalk is dosed by a pH controller which helps counter the drop at night. Without the kalk, it drops below 8.0 at night.

1). In your opinion/experience, what is the pH we should shoot for, for coral calcification, and is the reduced pH effect of a reactor on a system something that is problematic?

2). Also, would it be ok to run kalk at night and the reactor during the day?

3). Has there been any more tests done regarding the levels of strontium and other trace elements in reactor media? (Sprung & Delbeek cited some of your work saying that the Sr levels in most brands of reactor media were lower that that found in coral skeletons)

I just have the impression that no one running a reactor seems concerned about their pH, and the idea of disolving CO2 into my tank is a little unsettling.

Thanks again!

 

[tankslave]

One last thing, Sprung and Delbeek recomend Iron and Manganese additions, saying that these are rapidly depleted and may help polyp extension, etc. What is your opinion on this, and are these elements found in reactor media?

They also mentioned that chelated iron is not as "bio-available" as most manufacturers claim, since it is so tightly bound organically. I have yet to find an iron supplement that isnt chelated, so I was wondering how important iron/manganese was, in your experience, and if what Sprung and Delbeek said about chelated iron was true.

 

[Randy Holmes-Farley]

In your opinion/experience, what is the pH we should shoot for, for coral calcification, and is the reduced pH effect of a reactor on a system something that is problematic?

I'd aim for pH 8.2-8.5, but if the reactor will drive up the alkalinity, that offsets a pH drop in some respects.

Also, would it be ok to run kalk at night and the reactor during the day?

Yes, but stopping a CaCO3/CO2 reactor might allow it to become stagnant and possibly produce some hydrogen sulfide.

Has there been any more tests done regarding the levels of strontium and other trace elements in reactor media? (Sprung & Delbeek cited some of your work saying that the Sr levels in most brands of reactor media were lower that that found in coral skeletons)

I have not seen any studies since that came out.

I just have the impression that no one running a reactor seems concerned about their pH, and the idea of disolving CO2 into my tank is a little unsettling.

Actually, lots of folks with reactors also use limewater, and the limewater is just for the pH rise.

and if what Sprung and Delbeek said about chelated iron was true.

I do not know if iron is beneficial when there is no macroalgae, but I dose it for that reason. I discuss all these issues in this article, and the only info that is newly available to me is that Seachem sells an iron gluconate that might be a good one to use (even though they aim it for freshwater).

First Iron Article: Macroalgae and Dosing Recommendations
http://www.advancedaquarist.com/issues/aug2002/chem.htm

Second Iron Article: Iron: A Look at Organisms Other than Macroalgae
http://www.advancedaquarist.com/issues/oct2002/chem.htm