are skimmers bad

[Jeff]

i have been batteling cyno and hair algea on all my tanks for awhile, and i also lost a couple of candycane corals ever since i put on a decent skimmer on the 100gl tank. i have taken off or turned down all the skimmers and the cyno and hair algea are now receding. can some one tell me why this is happening? :blink

[matt]

Nope. I'm 99% certain that using a skimmer is not causing cyano or hair algae. The only possible connection I might be able to imagine with the loss of your coral would be if you had an ammonia problem and using the skimmer raised your ph (by raising O2 content) which in turn makes the ammonia more toxic by changing the equilibrium between free and ionized ammonia. That's a stretch, though.

Someone else might pipe in and say you're starving the coral by using the skimmer to remove DOM and particulates; believe me if your water was that clean, you'd have no nuisance algae.

[Jeff]

it seems that when ever i do something correct it never works out, but when i do something that you are not supposed to i seem to have better sucess.
i know that i'm not the only one that has had this happen to,Pete's tank had the same reaction and on rc there is a big topic on it.

[ratboy]

I've always been skimmerless and just recently decided since I had the space and my 400 came with a nice skimmer why not try it out. I can rem the brand but its a 6" diameter venturi skimmer run with a mag12. 2 days after running it my front glass was covered with a easy to remove red-brown algae. This persisted for the 1-2 months I ran it and now that I removed the skimmer the algae growth is decreasing. Are skimmer bad? I wouldnt go that far, but are the necessary? I say no.

--Erik

400 gallon softie/LPS tank
2x400W MH
ampmaster 3000 return
2 tunze 6100's
20 gallon fuge
DSB
Kalk reactor

[Instar]

Skimmers dissolve O2 in the water, but thats not the only thing. They also increase the level of dissolved atmospheric N2 in the water. Cyano has the capability to directly absorb disssolved N2 from the water and convert it into all the nitrates it needs to thrive. So, by changing the equilibrium of dissolved gasses and pH, this starts the cycle to balance the micro fauna and micro flora into a balance battle once again. And, after several months, once balanced with this new increase of O2, you'll like the way the corals look. But, there are many tanks with just a few fish and beautiful corals that are skimmerless, so its just a matter again of what a person wants to keep (and the limitations of the system chosen) and the amount of water changes a person wants to do. Skimmers remove waste products and ammonia before it becomes part of the nitrogen cycle, thereby keeping the fertilizers to a minimum overall. That one thing can be done with more frequent water changes too.

[GaryP]

I somehow doubt that Nitrogen is a limiting factor in Cyano growth. There is almost four times as much nitrogen as there oxygen in air. If your oxygen is at 6 ppm, that means that nitrogen is around 24 ppm. I may be wrong, but I don't see it. Also, cyano likes areas with low oxygen content, so reducing gas exchange by cutting off the skimmer seems to be counter intuitive. The other thing that cyano likes is dissolved organic carbon (DOC). Guess what a skimmer is removing in the collection cup?

Sometimes we often come to the wrong conclusion about things like this. Our systems are very dynamic. It is very easy to draw false conclusions from changes we make. There may be other things taking place that result in these changes and we come to the wrong conclusions based on what seems to be the most obvious change. I know I have been guilty of this as well.

Normally I would suggest the following to solve cyano problems.

1. Increase skimming (if possible) to reduce DOC and increase Redox potential.

2. Increase flow in the areas you are seeing cyano.

3. Increase the number of detritivores in the tank. Cyano likes areas where detritus accumulates. Increasing flow helps with this too by preventing accumulation zones. The detritivores will eat this stuff and excrete it as DOC that will be removed by the skimmers. Detritus not only provides DOC, but it also reduces the redox in the areas it accumulates because bacteria consume the oxygen in that areaa as they decompose the detritus.

4. Further decrease organics by mechanical filtration and carbon filtration.

5. Our tanks are usually deviod of any cyano grazers. A lot of different things will eat it. Queen conchs, margarita snails, and Naso tangs (supposedly). Leroy from GARF says that he has never seen anything eat cyano the way his red leg hermits (Clibanarius digueti) do. He collects these from the Sea of Cortez I believe. I am not sure if they are the same red legs we commonly see in the trade coming from Florida.

6. If all else fails, artificially increase redox with something like potassium permanganate or an ozone generator.

[matt]

Skimmers dissolve O2 in the water, but thats not the only thing. They also increase the level of dissolved atmospheric N2 in the water. Cyano has the capability to directly absorb disssolved N2 from the water and convert it into all the nitrates it needs to thrive.

I have never ever heard anything like this; how would the chemistry go for that one and given the large amount of (supposedly) dissolved nitrogen in aerated water, why doesn't it happen all the time?

Regarding the use of skimmers, it's pretty simple; skimmers are mechanical filtration devices that remove detritus and suspended waste before that stuff gets converted into ammonia and on down the nitrogen cycle. How can that possibly contribute to a nuisance algae problem?

Just like the use of KW, skimming is a proven effective filtration method based on many thousands of successful tanks over years of use.

[jroescher]

So after what Instar and GaryP say, does that mean that if you run a skimmer it should always be running to keep everything in balance, or is it okay to run the skimmer as needed or on a timer for certain times of the day?

[Instar]

Run the skimmer all the time and keep it clean.

Nitrogen is not a limiting factor at all. Its an alternate food source.

Matt, cyano has 2 different kinds of cells. Most of the cells are regular algae type cells but there is another cell type that can convert disolved N2 to nitrates for food. The filaments each have a strand of algae cells and one N2 fixiing cell center.

You can do what you want but there are many who will testify that they have changed water, filter the crap out of it, skimm it, don't feed the fish and have 0 for test results on every thing and are running 1,000's of gallons of flow and still have cyano. They guys who started skimmers on this post also said it showed on the glass where the flow is the highest and it showed up after they started the skimmer. The only way that could happen and it could pose such a nusiance without excess detritus and nitrates or phosphates is if it can fix dissolved atmospheric nitrogen. And it can. I didn't save the information about the cell types or names of the cells from the paper so rather than hazard a guess, I can't give you any more than this right now. The bottom line is cyano is extremely versitile and is photosythetic as well. It can grow in high flow areas, any area where there is a very slight current break (or eddy) or just plan in the current when it adapts. I've seldom, if ever, solved it simply with higher flow, it just seems to like that even more and can turn a tank into a mess.

Most cyano solving advice is far too simple or from some repeated partial advisory and the simple advice seldom if ever solves the issue for reef keepers. It takes several things to be successful; good competing cultures of algaes with well established bacterial balance, plenty of biodiversity, good flow all around without dead spots so oxygen is distributed and detritus is swirled into the filters and then some clean up crew and the correct light bulb spectrum (new lights, not old ones) and a measure of patience.

[Instar]

Run the skimmer all the time and keep it clean.

Nitrogen is not a limiting factor at all. Its an alternate food source.

Matt, cyano has 2 different kinds of cells. Most of the cells are regular algae type cells but there is another cell type that can convert disolved N2 to nitrates for food. The filaments each have a strand of algae cells and one N2 fixiing cell center.

You can do what you want but there are many who will testify that they have changed water, filter the stew out of it, skimm it, don't feed the fish and have 0 for test results on every thing and are running 1,000's of gallons of flow and still have cyano. They guys who started skimmers on this post also said it showed on the glass where the flow is the highest and it showed up after they started the skimmer. The only way that could happen and it could pose such a nusiance without excess detritus and nitrates or phosphates is if it can fix dissolved atmospheric nitrogen. And it can. I didn't save the information about the cell types or names of the cells from the paper so rather than hazard a guess, I can't give you any more than this right now. The bottom line is cyano is extremely versitile and is photosythetic as well. It can grow in high flow areas, any area where there is a very slight current break (or eddy) or just plain in the current when it adapts. I've seldom, if ever, solved it simply with higher flow, it just seems to like that even more and can turn a tank into a mess.

Most cyano solving advice is far too simple or from some repeated partial advisory and the simple advice seldom if ever solves the issue for reef keepers. It takes several things to be successful; good competing cultures of algaes with well established bacterial balance, plenty of biodiversity, good flow all around without dead spots so oxygen is distributed and detritus is swirled into the filters and then some clean up crew and the correct light bulb spectrum (new lights, not old ones) and a measure of patience.

[GaryP]

Most cyano solving advice is far too simple or from some repeated partial advisory and the simple advice seldom if ever solves the issue for reef keepers. It takes several things to be successful; good competing cultures of algaes with well established bacterial balance, plenty of biodiversity, good flow all around without dead spots so oxygen is distributed and detritus is swirled into the filters and then some clean up crew and the correct light bulb spectrum (new lights, not old ones) and a measure of patience.
I think that applies to any nuisance algae. There is no simple answer and it requires a strategy that addresses the problem on several levels: biologicval, chemical, filtration, and mechanical. I usually get a good laugh out of the posts that say "buy a tang," "cut your lights back," or "you need more snails." After I stop chuckling, I then get to work on one of those posts that I seem to be notorious for.

[J_G]

I think running Chemi-clean will get rid of cyano also wont it.

[GaryP]

It will, but its a temporary solution. It will come back unless you address the cause of the cyano in the first place (nutrients).

[Jeff]

well it has been a few days with it off and i have seen a reduction in cyno and green hair algea, not a lot but some.

[Instar]

What do you have for grazers to clean up the algaes? I'd opt to run the skimmer for the O2 sat it gives your corals and the clean up it does on the water and get some clean up crew to control the algaes. Once the algae cycles are under control (eaten down by the crew) then the coraline should take over providing you have a good balance of calcium and do regular water changes. Once thing to note, algaes like a clean oxygenated water to grow in better than water that is more dirty and void of oxygen so that may help to understand why they appear to grow better with the skimmer on. Take a look at the jetties if you doubt that. Lots of flow, many types of algaes. You will have algae cycles at first and then periodically because algaes have their seasons, even in a home reef. The clean up crew helps keep that under control.

[GaryP]

Jeff,

The other thing you may not be considering is that the skimmer is also removing potentially toxic organic chemicals from the water. Eventually those levels will build to the point that you will see negative impacts from them.

[Bbristow]

Amazing discussion. I have never heard of anyone questioning this.