To skim or not to skim?

[markc]

I built a skimmer for a friend some 10 months a go (Beckett DIY design)it works really well but we have noticed that the soft corals in the tank do not seem to be doing so well a very slow decline.
Water chem. is spot on SPS corals all doing well,could it be that the water is now too clean for the soft corals?

 

[MandarinFish]

I tend to believe in underskimming mechanically and letting animals and plants do most of the filtering.

 

[carver]

I have an opinion (that I think there might be some merit to this observation) but it is not based on science. I think this is an interesting question and just wanted to bump it back up so that hopefully one of our more knowlegeable people will respond.

 

[Anonymous]

That is the supposition among the experts. Althogh noone really knows what the skimmer pulls out, all the anecdotal evidence points to the same conclusion you came to. HTH

 

[randy holmes-farley]

I'm a proponent of skimming.

I stopped my skimmer for about 3 months to see what would happen to a variety of things (and just turned it back on a couple of weeks ago). The chemical changes I'll put into an article later, but for now I can say that I saw nothing positive by stopping skimming, and some negative things:

1. Flatworms began to grow much faster when the skimmer was off.

2. The pH in my tank (a limewater tank) ran much higher.

3. The algae on the glass grew faster without the skimming.

4. The macroalgae in the refugium grew faster when I turned the skimmer back on.

I noticed no apparent change in any coral throughout the experiment.

 

[Steve Richardson]

I wouldnt run a tank without a skimmer.

Partly because I feed fairly heavily, partly because I believe it helps to oxegenate the water, and certainly because it does pull out alot of waste.

I also believe 'overskimming' is overrated, as is its effect on trace element levels. Simply do a water change once in a while and feed a spectrum of rich food, and you have all the trace elements you could ask for and then some.

Mark - can you elaborate on the additives you use, species that are struggling, water changing schedule and anything else you might think is relevant?

Id bet my bottom buck that skimming is not the reason you are seeing declining softies. Do you run carbon and if not have you considered it?

babling,

Steve
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[Anonymous]

Randy,
Would you attribute the rise in pH to a higher CO2 concentration because the skimmer wasn't "blowing it off" ?

 

[jethro]

Skimming also pulls out minirals and nutrients.

Maybe your skimmer is too good.

Test your Calcium and Iodine levels etc.

Try putting your skimmer on a timer and cut back on its operation.

[ March 13, 2002: Message edited by: jethro ]</p>

 

[MandarinFish]

So.... why even skim unless you have a heavily stocked or overstocked tank? Is that the only reason to?

 

[aakks]

Wouldn't a higher CO2 concentration lower the pH not raise it? Isn't that the reason we're putting CO2 in calcium reactors, etc?

Peter

 

[randy holmes-farley]

Steve and Peter:

I attribute the higher pH to the tank not pulling CO2 from the air as rapidly.

 

[Anonymous]

I do not think you are over skimming. I think you are not adding enough trace elements. Softies seem to love,if not need,iodine in higher concentrations then the occasional water change or feeding. They also require the other trace elements as well.

I agree with Randy. Since I added a better skimmer the diatoms and microalgaes have all but disappeared. I also noticed that the algae in my refuge has been growing better too. I cannot comment on the flatworm issue and being I had a skimmer on the tank prior to the upgrade I didn't notice a difference in PH. I see no reason to go skimmerless. The benefits outweigh the drawbacks IMO.