What does "over skimming" actually mean?

[MikeBrke]

I ask because it seems this is the directions alot of people are going with their tanks. For example, people using skimmers rated for 150 gallon tanks on their 90 gallon (sps dominated, light/medium stocked) tanks?

So:
1) what is "over skimming" and how is it bad?

2) Is it theoretically better to over skim? Is their a real benefit or is it the "bigger is better" mentality?

Thanks,

Mike

 

[HowardW]

Over skimming may not be desirable for some tanks that have mainly soft corals and may prefer slightly 'dirtier' water.

However many SPS coral keepers and those with heavy fish loads may say there is almost no such thing as over skimming.

 

[m2434]

I don' think there is really a standard definition. In theory, it essentially means that you are actually removing more than just organics (i.e. so much skimming you may be removing trace elements). This definition however is not really testable for the average hobbyist and I think the working definition is using a skimmer that is rated for a much larger tank, but this is very subjective.

 

[King-Kong]

Re: What does "over skimming" actually mean?

<a href=showthread.php?s=&postid=11014317#post11014317 target=_blank>Originally posted</a> by MikeBrke
I ask because it seems this is the directions alot of people are going with their tanks. For example, people using skimmers rated for 150 gallon tanks on their 90 gallon (sps dominated, light/medium stocked) tanks?

So:
1) what is "over skimming" and how is it bad?

2) Is it theoretically better to over skim? Is their a real benefit or is it the "bigger is better" mentality?

Thanks,

Mike

To me, to be "overskimming" is to be removing too many nitrogen sources from the tank before your corals can uptake them.

In bare-bottom tanks you sometimes see this, which can lead to pastel and faded corals.

The size of your skimmer in conjunction with how much you feed will dictate this..

I have a BM250 on a 90 gallon, but I still have 7ppm nitrates and dark tissue on my corals -- my skimmer may be "oversized", but it is not "over skimming".

 

[Aquarist007]

Re: Re: What does "over skimming" actually mean?

Re: Re: What does "over skimming" actually mean?

<a href=showthread.php?s=&postid=11014618#post11014618 target=_blank>Originally posted</a> by King-Kong
To me, to be "overskimming" is to be removing too many nitrogen sources from the tank before your corals can uptake them.

In bare-bottom tanks you sometimes see this, which can lead to pastel and faded corals.

The size of your skimmer in conjunction with how much you feed will dictate this..

I have a BM250 on a 90 gallon, but I still have 7ppm nitrates and dark tissue on my corals -- my skimmer may be "oversized", but it is not "over skimming".

agreed but to add---if you have a good size refugium, live rock and a deep sand bed then you don't need to really over skim---it still necessary though to have an effecient skimmer.

 

[m2434]

If you were removing nitrogen sources before your orals could take them up, the corals would die (fading is like slow dying, right?). This would be over-skimming, but I don't think this is what's meant when people use the term. As I said, the term, as used in the hobby, is very subjective. I think HowardW made a good point. Having more organics in the water column gives soft corals a competitive advantage and removing them shifts the balance twords other more sensitive corals. I think getting to this level of skimming may be a common conception of "over-skimming". However this would just mean the nitrogen sources are too low for coral a, but not for coral b. Ussing this definition, you would need to define what is required by coral a and coral b, to define over-skimming. Then what if you are skimming more than this, to the point that coral c now has the advantage. My point is that, this is simply a huristic way of thinking about hom much nutrient export is occuring. Diffrent organisms thrive in diffrent conditions and there probably an optimal balance for your particular tank.