Skimmer got you covered, think again.

irie ivan

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It is a well known fact amongst reefers that to obtain vibrant coloured sps, we need to reduce/eliminate dissolved nutrients. For a good number of years, the first line of defense for the hobbyist has been mechanical removal of particulates, before they can break down into dissolved nutrients. Nothing wrong with the thinking there!
The primary instrument in the hobby for this purpose is the proteinskimmer toted for overall, near maximum removal of dissolved and particulate organics.

We all know the order of filtration should be:
1.) Mechanical: To remove as much particulate matter as possible, reducing worload of biological filtration.
2.) Biological: Removes what the mechanical filter "missed", breaks it down and uses the turning the broken down products into biomass.
3.) Chemical: To polish water. Last in line, often Expensive adsorbents/ ion exchangers, last in line to prevent their clogging and extend their lifespan.

1.) Skimmer
2.) DSB, algal scrubber, fuge
3.) Carbon, purigen, PO4 media.

The way most tanks incorporating a sump is set up?

Which brngs me to my question:
Just how efficient is your skimmer at removal of particulate matter?
How would you answer that?
Because different types of skimmers use different techniques (threadwheel, needlewheel, venturi, downdraft, beckket, etc), the ratio of dissolved nutrients to particulates varies for each type. Foam concentration mechanism, height of neck, siphon break, reaction time, slope of junction between chamber and neck all come into play here. So lets be honest here, we do not really know what our skimmers are removing, nor do we know the ratio.
So if we don't know what are skimmers are removing, how do we know what they are missing? OR, most importantly

Considering my system volume (600litres) and light bioload (minimal fish), I definitely do not have a shortfall in the skimming department. I run a 3 pump reef octopus, equivalent to the reeftek ts4, rated from 1500 litres to 2000litres, as well as a MAD venturi, rated for about 800 litres.
Some pics for those getting bored:

My skimmer, and what it removes in 36 hours::
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With a properly set up and maintained dsb, the micro and meofauna would take care of detritus missed by the skimmer, followed by further consumption by bacteria.
Unfortunately, I doubt whether even 10% of aquarists in SA have sufficient pupulations of detritivores in and on their dsb's to process what their skimmers miss.
(I am yet to find a regular supply of detritivore, live sand recharge kits, as sold in the states.) Lets be honest, unless you live along the east coast, or visit there regularly, you have no hope on running a dsb in the way proposed by the likes of Shimek. So that leaves most of us with dsb's run primarily on a bacterial population. If you think a primarily bacterial population can process even a lightly stoked, heavily skimmed tanks detritus, disturb some topsand from your dsb and measure the PO4 content. You will be UNpleasantly surprised. (I know I was)

Having discovered the source of my PO4 readings (0.9 hanna photometer), i comitted to fight this accumulated nuisance algae nutrient problem waiting to happen. (I did not have an algae issue, and my sps colours were great) Surely if if physical matter(ie particles) can be removed PRIOR to skimming, it allows even better SKIMMING..nomatter the skimmer type/technology.

Installed a prefilter in before my skimmer:
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, and not content that tis was enough to eliminate detritus settling on my dsb, i installed one before my dsb as well. (no pic, as too difficult to get camera in there)

The filter floss is thrown away at least once every 36 hours, and the filter matting is washed with hot water and thuroughly rinsed to remove detritus, bacteria and uneaten food.
Filter matting is changed for new ones once per week!
Be sure to thoroughly rinse the filter floss and the filter matting very well in freshwater before using for the first time, as it will cause your skimmer to go insane.

The inside made up with filter floss and filter padding:

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Now the shocking part:

On the left, clean filterfloss, on the right, the pre filter before the skimmer after 36 hours:
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On the left, clean prefilter and on the right prefilter after the skimmer sump after 36 hours:
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The upper part of the filter matting in the after skimmer sump after 36 hours, compared to clean filter matting at the top:
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Clearly this is case in point for mechanical filtration before skimming and again after skimming. Strange that it is seldom mentioned in aquarium literature, and where it is, seldom more than a paragraph is dedicated to it.......

Perhaps because it requires more work, (must be washed out at least every 36 hours to prevent breakdown into nitrate) or perhaps because it is not a high tech piece of equipment we can debate about. Question remains, why are so few using it???

The results speak for themselves:

I managed to get my PO4 down to 0.00 (photometer), nitrate down to undetectable levels (seachem kit, measured at 3ppm before i started) by syphoning the top layer of my dsb and blasting clean LR. I have increased my bioload, from 2 fish to 10 in a week (don't try this at home), tripled my feeding and still my po4 reads 0.00! Oh and yes, my dsb remains a hell of a lot cleaner than ever before!
 
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Reef Inmate

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I have always believed in mechanical filtration. The trick is to clean it often. Where does one get a prefilter like that or did u make them?
 

Alfie

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Ivan, this has been an interesting read to say the least. Couple of questions. Do you cover the inside of the lid with floss as well? How long after installing did you manage to reduce you PO4 to 0.00.
 

Kanga

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Great thread Ivan, I have filterfloss on my overflow pane from Skimmer chamber to DSB, and change twice a week, mine is dark brown when I remove it and I also think it helps with the clarity of my water.

I do get a few concerned looks when I tell people I use it:p
 

Tom

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I use floss in a cannister and wash it each night. It really helps keep the water clear.
 

jacquesb

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Thanks for this thread Ivan! It really goes to show that there's ALWAYS something that we SHOULD be doing (and this could be as low-tech as you pointed out), to try and rid our tanks of the most problematic of all nutrients: PHOSPHATES!
Thanks again!
 

Smithers

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Irie is it worth removing the top layer of sand from the dsb and replacing it on a monthly basis. Not talking about a massive amount maybe the top half a cm.

To recharge your dsb can you get fresh sea sand and add that.

BTW great idea with the filter floss.
 

moz

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I've followed Kanga's example filterfloss on my overflow pane from Skimmer chamber to DSB, catches a lot of crap especially when I clean my glass.
 

DragonReef

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Excellent thread Ivan. Thanks.
 

Alan

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Personally i have nothing against the use of filter floss as a mechanical filter and in fact the more varied your filtration in a system the better. My only resevation is when using the filter floss you have to be disciplined to clean it out regularly other wise it will have the opposite affect on your system ie it will lead to an increase in Nitrates and Phosphates.
 

irie ivan

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The trick is to clean it often. Where does one get a prefilter like that or did u make them?
They are sold for pond filtration. Busy designing a more practical one, made from better material, and more suited for marine use.

Do you cover the inside of the lid with floss as well? How long after installing did you manage to reduce you PO4 to 0.00.
No, the top part of the lid i left without floss, as in the event of a blockage, water will flow through the holes (enlarged holes with a soldering iron), rather than back up into my overflow and empty my sump/tank on the floor. (salt too exppensive to mix for that!!!)
It took me a month to bring my PO4 down to 0.01 with water changes, blasting rocks clean, removing some of the sandbed, etc. My PO4 has been steady at 0.00 for two weeks now. Peaks at 0.01 a few hours after feeding.

Irie is it worth removing the top layer of sand from the dsb and replacing it on a monthly basis.
Absolutely. However, with minimised detritus settling on the dsb, I now just siphon the s,all mounds of detrtus and surrounding sand, was sand well in ro, soak for a few days and put back in. No need to remove the whole top layer anymore.
Excellent thread Ivan. Thanks.
Pleasure!!! Don't thank me, send me frags!!! purple loripes ring a bell.....
My only resevation is when using the filter floss you have to be disciplined to clean it out regularly other wise it will have the opposite affect on your system ie it will lead to an increase in Nitrates and Phosphates.
True, BUT, when you see 0.9 on a photometer (90 times where it should be), even with great colours, you realise that all is not as well as you thought......
NO option but discipline!!!
 
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viper357

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Awesome info, thanks Ivan, thread stickied.

Do you have holes in the bottom of the cup as well?
 

irie ivan

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yes, small holes, about 1mm each. thinking of encreasing their size.
 

SIMS

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IYO would a glass box filled with filter floss work for the overflow pipe...I been playing with this idea for a while now?

I could also fut in a floss box after the skimmer...?
 

Galibore

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One more (possibly dumb) question:

Does doing this not impact on your pod population? Surely eventually all the pods will end up in the filter floss?
 

SIMS

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One more (possibly dumb) question:

Does doing this not impact on your pod population? Surely eventually all the pods will end up in the filter floss?
True but if you put it before your refugium it should not be a problem...
 

Galibore

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Good question Gali - I can only presume that the refugium is in a completely seperate tank then, that is not/should not be impacted at all?
True but if you put it before your refugium it should not be a problem...
What about pods traveling over the overflow towards the sump. They will be trapped. I think I am going to try this and see how many (if any) get caught.

Thanks for the awesome thread Irie!
 

SIMS

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Yea some will get trapped but if you have a dig enough refugium you should be ok (just a guess as I have no idea)
 

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