The mysterious over skimmed aquarium.

[skriz]

Most ratings are completely made up. You'll find the same practice in every industry. Cheap amps boast high wattage ratings, but in reality they're completely bogus. I'm sure the same applies to woodworking tools and equipment.

Now, how do you properly rate a skimmer?
1. Water turnover rate
2. Biology (a scientific measurement)
3. Bubble density, which relates to air and water throughput.
4. Dwell time

This is what we do to determine our skimmer ratings. They're then field tested and documented. We compare that data to our theoretical data and adjust the ratings if need be.

This is why you'll find a $200 skimmer rated for 500 gallons and a $1300 skimmer rated for 500 gallons. Somebody isn't being honest.

 

[mufret]

It is a function of bioload and skimmer size which can be frustrating and most manufacturer's rating I've found to be suspect (some certainly better than others) and have no idea how they come up with their numbers.

 

[grouper therapy]

Skriz;1077010 wrote: Most ratings are completely made up. You'll find the same practice in every industry. Cheap amps boast high wattage ratings, but in reality they're completely bogus. I'm sure the same applies to woodworking tools and equipment.

Now, how do you properly rate a skimmer?
1. Water turnover rate
2. Biology (a scientific measurement)
3. Bubble density, which relates to air and water throughput.
4. Dwell time

This is what we do to determine our skimmer ratings. They're then field tested and documented. We compare that data to our theoretical data and adjust the ratings if need be.

This is why you'll find a $200 skimmer rated for 500 gallons and a $1300 skimmer rated for 500 gallons. Somebody isn't being honest.

So is it possible to over skim as in pull too much organics out?

 

[ghbrewer]

grouper therapy;1077007 wrote: How was that ever determined?

They likely pulled it out of where the sun don't shine...lol

No, but really, like Mike stated, most of it comes down to the size of the neck and all the stuff Raj mentioned.

When I was running that NYOS Quantum 180 on my office tank, it never built a good foam head. So, no skimmate made it up to the cup. This is what I got when I downgraded to the Quantum 120:

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That was about a days worth.


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[ghbrewer]

grouper therapy;1077012 wrote: So is it possible to over skim as in pull too much organics out?

Everything I have read points to no. I don't think a skimmer can pull "all or too much" organics from the water column. If you want to dive into it some more:

http://www.advancedaquarist.com/2010/1/aafeature">http://www.advancedaquarist.com/2010/1/aafeature</a>



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[seth the wine guy]

A washdown on a timer makes posts worried about "film" or "head" irrelevant. Ever watch a washdown in a skimmer happen? For those that haven't, any stoppage of foam or head in the neck is immediately projecting itself up excitedly spilling into the skimmer cup.

I'll take a video and post it next time I have a chance. Having a massively oversized skimmer for my tank allowed for me to chum the water with food like I was fishing for shark but quickly pull it out when my 30 minute feed cycle with the return pump off was over.

I wanted to do the same for my next tank, but, some dang public aquarium bought the skimmer out from under me.

 

[ghbrewer]

Wash downs are nice, I think that I saw yours in that tank wars video. Though for this discussion, not sure it really applies since "generally speaking" most people aren't running a $$$$ recirculating MRC skimmer with all the bells and whistles...lol


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[seth the wine guy]

With all the resourceful diy folks around here running a tank with a controller, I'm sure it can be done with nearly any skimmer as long as you have a way to run a drain line from your skimmer cup or simply be willing to dump it daily. And since the topic is about over skimming, I doubt the skimmer to be modded would be that small.

 

[seth the wine guy]

Below is a quick video. Right now, I'm in the process of transferring everything from one tank to its next home. I had to bulldoze my sump room outside. I have everything running in a temporary setup in the middle of the room so I don't have the wash down on it regular every 4 hour timer. So, stuff gets really chunky in the neck and when the wash down kicks in, it throws large chunks of gunk into the skimmer body. Ideally, it's done often enough that a build up like that doesn't happen and just foam ejects into the neck. It's still not a big deal for me having it get chunky because the skimmer discharge goes directly to a filter sock. So, it's either caught there or skimmed back into the neck.

<!-- gcu-updated ame -->https://youtu.be/PhgqaTkAdo4<!-- gcu-updated /ame -->

 

[skriz]

grouper therapy;1077012 wrote: So is it possible to over skim as in pull too much organics out?

No. The skimmer will effectively shut down when there's not enough left to skim. But, since you're constantly producing waste, that's a short lived shutdown.

There's a big coral wholesaler who only runs our skimmers for 12 hours a day due to this. The skimmers are cleaning the water faster than the waste is produced and since this is a very controlled environment, it made sense for them to run them on timers and reduce their peak power consumption.

Like others have said, you can oversize (or undersize) a skimmer, which just becomes a waste of money. If you take the stats (poundage of fish, poundage of food added, etc.) and calculate what you need, you can spec the skimmer correctly. However, this assumes the skimmer ratings are reliable in the first place.

 

[lsu_fishfan]

Seth The Wine Guy;1077045 wrote: Below is a quick video. Right now, I'm in the process of transferring everything from one tank to its next home. I had to bulldoze my sump room outside. I have everything running in a temporary setup in the middle of the room so I don't have the wash down on it regular every 4 hour timer. So, stuff gets really chunky in the neck and when the wash down kicks in, it throws large chunks of gunk into the skimmer body. Ideally, it's done often enough that a build up like that doesn't happen and just foam ejects into the neck. It's still not a big deal for me having it get chunky because the skimmer discharge goes directly to a filter sock. So, it's either caught there or skimmed back into the neck.

https://youtu.be/PhgqaTkAdo4">https://youtu.be/PhgqaTkAdo4</a>[/QUOTE]

Seth, how do you achieve this type of skimming? Do you start with the foam level low in the body and let it build up over time?

 

[seth the wine guy]

The foam head starts low in the neck and will crest and spill over into the cup by itself on heavy feed days but generally crests just below the top until the washdown kicks in making it all jettison up and out.

I can't say if how I do it is the ideal way for someone wish a washdown. The method seems logical to me but I'd defer to Raj for recommended washdown practices.

 

[saltwaterwannabe]

Newbie learning here, so forgive me if this question sounds ignorant....if the skimate never reaches the cup until washdow, wouldnt that mean that the surface tension at the top of the foam is not strong enough due to the neck being too large, resulting in a lot of nasty stuff passing throuh the skimmer without being collected?

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[grouper therapy]

If a lot of stuff was present then the foam head would be bigger.

 

[grouper therapy]

I think a lot of this has to do with ones feeding regimen. I ,like Seth ,will bombard if you will my tank with a lot of food and I do this twice a day so I don't care if the skimmer is idle until I feed them I want it to be big enough to handle the load and not take all day to do it.

 

[saltwaterwannabe]

Sounds reasonable

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