Let's talk about bio load.

[sphelps]

Over-skimming has nothing to do with removing beneficial bacteria, while such bacteria exists in the water column the amount of it compared to what attaches to surfaces in basically zero. Skimming removes bacteria about as effectively as water changes. Over skimming removes desirable elements such as potassium which can effect coral health. This can be avoided even with grossly over-sized skimmers by dry skimming rather than wet skimming and dosing to compensate.

In terms of zeovit the system is based on strong skimming, I remember previous versions of the guide actually stated you couldn't use a skimmer that was too large however that probably resulting in some using ridiculously over-sized skimmers meaning elements where depleted faster than they could be added. Thus the added note stating not too use a skimmer "too oversized" but you should still use an "over-sized skimmer". Also nothing official from zeovit suggests shutting a skimmer off during dosing, only to dose downstream of the skimmer in order to give the bacteria a chance to populate within the aquarium (same for the reactor mull).

Originally Posted by ZeoGuide

As mentioned earlier, the basis of this method relies on export of harmful substances through skimming. Continuous use and frequent cleaning should be conducted in order to keep the skimmer performing at its maximum level. The results are better when the skimmer is adjusted in order not to produce too much concentrated skimmate (wet skimming). We would like to point out that it is our thought that needle wheels may precipitate certain elements and destroy plankton. These elements, e.g. such as potassium, will need to be re-added to the system. Do not use a skimmer that is too oversized or employ wet skimming if you use a needle wheel skimmer. We recommend the use of venturi type skimmers.

[mikellini]

Originally Posted by sphelps

Over-skimming has nothing to do with removing beneficial bacteria, while such bacteria exists in the water column the amount of it compared to what attaches to surfaces in basically zero. Skimming removes bacteria about as effectively as water changes.

This isn't exactly true... For example, systems in which organic carbon is dosed remove a lot of bacteria via foam fractionation (skimming). This is actually the primary way in which such systems control phosphates; by removing the bacteria that bind/use/consume them from the aquarium. Also why skimmate colour changes significantly when dosing carbon (ethanol, vinegar etc). Zeovit systems also remove a substantial amount of bacteria by skimming; when the 'mulm' (basically bacterial biomass) is shaken and released, whatever isn't immediately eaten or otherwise used by the inhabitants is skimmed out.

[sphelps]

Originally Posted by mikellini

This isn't exactly true... For example, systems in which organic carbon is dosed remove a lot of bacteria via foam fractionation (skimming). This is actually the primary way in which such systems control phosphates; by removing the bacteria that bind/use/consume them from the aquarium. Also why skimmate colour changes significantly when dosing carbon (ethanol, vinegar etc). Zeovit systems also remove a substantial amount of bacteria by skimming; when the 'mulm' (basically bacterial biomass) is shaken and released, whatever isn't immediately eaten or otherwise used by the inhabitants is skimmed out.

Yes and what exactly does that have to do with over skimming? We're talking about two different things.

[Proteus]

Thanks Denny that's a long read but very good

[mikellini]

Originally Posted by sphelps

Yes and what exactly does that have to do with over skimming? We're talking about two different things.

You said that skimming removes about as much bacteria as a water change, which really isn't the case. It sounded like you didn't understand how skimming worked.

[mrhasan]

[sphelps]

Originally Posted by mikellini

You said that skimming removes about as much bacteria as a water change, which really isn't the case. It sounded like you didn't understand how skimming worked.

A skimmer can only remove bacteria from the water column, same as just removing the water. Bacteria adheres to surfaces significantly more than the water itself thus removing the water or skimming heavier will not diminish a bacteria population period. This applies to carbon dosing or zeo, over skimming has no negative effects on a bacteria population, even if you're dosing it provided you dose downstream. So my point was when over sizing a skimmer to your bio-load the risk relates to removing excess essential elements such as potassium not bacteria. Make sense yet?

[mikellini]

Originally Posted by sphelps

A skimmer can only remove bacteria from the water column, same as just removing the water. Bacteria adheres to surfaces significantly more than the water itself thus removing the water or skimming heavier will not diminish a bacteria population period. This applies to carbon dosing or zeo, over skimming has no negative effects on a bacteria population, even if you're dosing it provided you dose downstream. So my point was when over sizing a skimmer to your bio-load the risk relates to removing excess essential elements such as potassium not bacteria. Make sense yet?

I understood your central point from the start, however saying a skimmer removes as much bacteria as a water change was mixed in there. Fact is, you can't compare the two. And truthfully a skimmer can remove a lot of bacteria.

[sphelps]

Originally Posted by mikellini

I understood your central point from the start, however saying a skimmer removes as much bacteria as a water change was mixed in there. Fact is, you can't compare the two. And truthfully a skimmer can remove a lot of bacteria.

Disagree, if for some reason I wanted to remove bacteria from the water column I could change 100% of the water which would be far more effective than what a skimmer could do. Ultimately changing a given amount of water on a certain frequency would compare directly to what a skimmer would accomplish, same as removing any organics. But that's all pointless information irrelevant to anything we're talking about here, the comparison was only made based on the common misconception large water changes are harmful because they remove beneficial bacteria, so I was making the same comment relating to large skimmers...

[reefwars]

Some reading for anyone who's interest in bacteria numbers , removal and what carbon dosing does to certain bacteria.

http://www.advancedaquarist.com/2011/3/aafeature