cheato and refugium......

[puffdaddy_1]

Randy,

About a month ago I setup my refugium on my 72 gallon. I was running an old skimmer and nitrates were around 40-60. This refugium is a hang on the back so it gets lid during my photo period under hqi 250 metal halides. The lighting system is only a month old so the lighting is very good and intense. At first I put a handful of cheato in the refugium. It nearly tripled its size in a matter of days under these halides. For the first 3 weeks it was just growing like crazy. About a two weeks ago I harvested a lot of it out leaving about a handful of it in the refugium. It now seems to be growing very slowly. I tested my nitrates and they were at 20 ppm. So it did do some damage. Could it be that trace elements have been used up that this macro uses and is causing slow growth??? Since this macro was growing at such a fast pace under the intense lighting, it was also using trace elements just as fast??? I last did a 10% water change about a month ago. Should I be dosing any additives for this macro? What do you think is the cause for the decline in what was once such rapid growth??



I appreciate your response

[Randy Holmes-Farley]

It may now be limited by phosphate, or possibly iron (I dose iron for macroalgae). It is also possible, although less likely, IMO, that it is limited by something else.

You can dose iron, and you can measure phosphate to see if it is very low.

These articles may help:

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

Phosphorus: Algae’s Best Friend
http://www.advancedaquarist.com/issues/sept2002/chem.htm

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/issues/august2003/chem.htm

[cloudancer]

I'm seeing a very similar problem. My cheato was growing gang busters until about a month and a half ago, then is stopped almost overnight (not dying, just not growing very much). Since then my problem algae problem has taken off. I didn't change my lighting or anything else at that point.
I'll assume my phosphates are probably high enough and its most likely iron given the micro-algae growth unless someone has more thoughts on what it is.
I've also started loosing some SPS to bleaching and have attributed it to the cheato growth problems. Is that likely or am I seeing something else?

[Randy Holmes-Farley]

It is possible that elevated phosphate is the problem with both the microalgae and the SPS. Iron may be helpful,or not. It is at least worth a try. :)

[cloudancer]

Ok, That confuses me a bit. I thought the macro-algea was a consumer of phosphate, not restrained by an excess of it? In any case I put in some phosphate absorber, if that's the problem it should be easy to fix pretty quickly. I'll also test for it in a bit.

Thanks for the help :)

[Randy Holmes-Farley]

I was suggesting that phosphate was a problem with the excessive MICROalgae growth, not a cause of poor growth of macroalgae. :)

[cloudancer]

Ok, my mistake. I must admit it makes a LOT more sence that way :).

[Randy Holmes-Farley]

No problem. Happy Reefing. :)

[puffdaddy_1]

Randy,

Have you heard of any reefers experiences with iron saying if it made a difference in macro growth? I was just wondering what some peoples experiences are with dosing iron.

I appreciate your response

[Randy Holmes-Farley]

Absolutely. Many folks, including a number of the RC Staff have had pale and poorly growing Caulerpa turn darker green and grow faster on iron addition.

I initially got turned on to it years ago when my refugium was being overrun with microalgae growing right on the macroalgae. Some kind soul suggested that iron could boost the macroalgae at the expense of the microalgae, and that turned out to be the ticket for me.

I discuss the effects of iron a lot more in the articles linked above.

[puffdaddy_1]

Looks like I will be trying an iron supplement.

Thanks Randy

[lmuller1]

Can there be any ill affect to the main tank when dosing the refugium with iron. Should iron be tested for before adding it to the refugium.

[Randy Holmes-Farley]

I discuss the effects on a variety of organisms in the second article linked above. I've not heard of any ill effects, but I would not dose iron if I did not have macroalgae. In that scenario, it might just boost microalgae.

IMO, there is not a suitable kit available to know the available iron levels in reef aquaria. Even with the best instrumentation, I'm not sure what level one would target or how one would know that the iron detected was bioavailable or not as there are many forms.

As with anything new, start slow and stop if things look worse. :)

Looks like I will be trying an iron supplement.

Thanks Randy

You're welcome. :)

[puffdaddy_1]

Randy,

Im seeing an immediate impact on my macro algae growth with the iron addition. I have a hob fuge, so the macro grows under my halides pretty fast. Looks like the iron additive is what I needed.

Thanks Randy for the advice!:celeb2:

[Randy Holmes-Farley]

That's great. I'm glad it helped. :)

You're welcome and Happy Reefing.