Overskimming?

[Untamed12]

To give a brief history before asking the question...

I battled cyano for quite a time, doing everything I could think of for nearly 6 months. I finally concluded that I had to replace my skimmer with a larger, better model. I did that, and the cyano immediately disappeared.

As soon as the cyano left, my tank thrived....for about a month.

Then, my soft corals began to close up. SPS seem very happy.

I do weekly 10% water changes, and have been doing double that for the past 2 weeks trying to rectify whatever is going on.

So I suspect that I am now OVER skimming. The question is...What would be the first compound/element that I would loose in an overskimming situation...and would I see that affecting soft corals first?

...I suppose that a possible solution would be to cycle the skimmer..but I would rather not do that.

 

[Randy Holmes-Farley]

It may well be possible to strip too much in the way of organics and/or other nutrients from the water for somne soft corals.

Are you feeding the tank?

What skimmer now?

 

[Untamed12]

I went to a Euro-Reef CS6-1. They would call it a CS-100 now.

http://www.euro-reef.com/csrs100specs.shtml

Given that I have less than 40 gallons in total, I'm skimming pretty good!

As I try to keep a large variety of LR life alive, I feed heavily for the 3 small fish that I have in the tank. I also feed DTs phytoplankton daily.

There are a few things that I've never had success with...Xenia for example....but my star polyps and leather coral were quite happy for quite a while. My lights are fresh, but not brand new.

I dose Kalk 24/7 using a pump as my only source of Ca/Alk. Ca is stable at around 360..but Alk tends to fall and requires supplementation almost every few days. Kalk doesn't seem very balanced for me...but that is probably a different thread!

 

[Randy Holmes-Farley]

Xenia is an odd duck. It thrives in some tanks and not others, and sometimes seems to do better in newer tanks. Perhaps it does like more of at least some nutrients.

Ca is stable at around 360..but Alk tends to fall and requires supplementation almost every few days. Kalk doesn't seem very balanced for me...but that is probably a different thread!

That is the usual sign that you are not adding enough of a balanced additive. I discuss that in this article:

When Do Calcium and Alkalinity Demand Not Exactly Balance?
http://reefkeeping.com/issues/2004-12/rhf/index.htm

 

[MiddletonMark]

Beyond Randy's obvious important question ... IMO feeding might be a small part of the equation too.

I found with my BB tank, heavily skimmed ... that when the tank started to get `clean' - IMO things did much better with very regular feeding of fish/coral mush.

The phrase for what I like to think I'm trying to replicate [the reef] is `nutrient poor and plankton rich'. IMO, you may be getting nutrient-poor with your skimmer now ... time to add food/plankton. Don't overshoot what your skimmer can handle ... but if the tank can export it, IMO why not feed a little more?

 

[Untamed12]

As usual...an excellent read. Thanks. (I thought I had read every one of your articles, but I did miss that one somehow)

I will raise my Kalk input and watch what happens to alk.

That wasn't what started this thread, but I've learned something anyway.

Has it been well established scientifically that you actually CAN overskim a system? Does the skimmer actually remove elements that are necessary for some life (like soft corals)? If the skimmer can do this....does anyone know what elements are removed and which go first?

 

[Randy Holmes-Farley]

Has it been well established scientifically that you actually CAN overskim a system?[?B]

Not in the sense of side by side comparisons of coral growth rates, at least not that I have seen. Skimming and carbon both have the potential to remove many things. Skimmate has been analyzed and it has tons of different things in it, but without knowing what levels might be critical in the water, and whether the water has sufficient of those or not, one can't determine if overskimming is an issue or not.

This article may be useful:

Reef Aquaria with Low Soluble Metals
http://reefkeeping.com/issues/2003-04/rhf/feature/index.htm

 

[Randy Holmes-Farley]

This one shows what is in skimmate:

Down the Drain, Exports from Reef Aquaria
http://www.reefkeeping.com/issues/2002-12/rs/feature/index.php

 

[euroreef]

Untamed12,

Regarding fluctuating alkalinity levels: Maintaining natural levels of Magnesium (+/- 1300 ppm is good) will help stabilize the calcium and alkalinity fluctiations. I would also check Iodide/Iodine levels as softcorals are fairly sensitive to a lack of Iodine. As far as xenia goes, with ample Iodine and soft coral supplements, as long as the pH is on the high side (8.3-8.5), they will generally thrive.

-ER