How do get more out of your skimmer

[aquavista99]

How to get more out of your skimmer by Anthony Calfo  [http://reefcentral.com/forums/showthread.php?s=&threadid=554786]


Daily skimmate production is an ideal that anyone can reach, presuming you want to use protein skimming as your primary means of (aggressive) nutrient export. There are of course many ways to run a healthy system with less skimming or no skimming at all. But that’s not what we are chatting about here.

When you see a 240 gallon tank that gets no food, has no fishes, monospecific for Xenia, and only dry sand and dry rock for substrates (no LR or LS for fear of bringing in pests, predators or nuisance algae)... and the tank still yields 4-8 oz of coffee dark skimmate (!), you'd be converted too.

So... why don’t you get such daily skimmate? There are many common reasons for this.

The number one reason is the quality of water delivered to the skimmer.

Anything less than raw water overflowed straight into the skimmer is a compromise.

Hence the popularity and track record of Tunze rail- and top mount skimmers (they sit at the surface of the water).

I understand that this is not always practical. Top mount skimmers are unsightly, and not everyone can or wants to plumb their overflow directly into the skimmer instead.

So what’s the next best thing? Well... overflowing raw water into a narrow and concentrated skimmer vessel (just slightly larger than the footprint of your sump model skimmer... or really... just the pump that feeds the skimmer). The easiest way to accomplish this is to seal a partition in the sump if the sump is large enough. Else, just get a small plastic or glass vessel (again... just large enough to squeak the skimmer into) and drill it to overflow into the sump. It will, of course, be kept next to and slightly higher than the sump for this strategic position between the overflow and the sump proper.

If instead you simply sit your skimmer in an open sump... you may just want to unplug it and save the electricity.  I'm guessing you get a full cup of skimmate out of that skimmer once weekly or less. It’s no great surprise. Some skimmers can perform well this way... but most do not. And it’s as much to do with size (small) and flow (high) of the sump that makes skimmers in open sumps work at all.

The problem with the majority of skimmers installed (and working poorly) in open sumps is that the fluctuation in water level (turbulence and/or evaporation) slightly affects the head (pressure) on the pump and in turn the amount of water forced into the skimmer. The open sump with slower flow also wreaks havoc on the collection/concentration of proteins (they can migrate back to the surface of the water as they do in the main tank) above the level of the skimmer pump in this case.

That reminds me of the problem with HOB skimmers... their feed pump is drawing water from several inches below the surface of the tank. Wanna improve HOB skimmer performace? Raise the powerhead as close to the surface as you can. Its not as good as getting overflow water (better concentration of surface protein overflow water)... but it is a huge help.

Back to those sump model skimmers... if you cannot seal a partition into your sump... and if you cannot fit a skimmer tank next to or above the sump... then stick the skimmer in a bucket in the sump so that it sticks up above the active running sump water level. Feed this bucket with (again) raw water from the display above, and simply let it overflow the sides of the bucket into the sump proper.

Another big design flaw of skimmers... poor exit control of water. Better skimmers have a gate valve (not a ball valve) for fine control and adjustments. Poor skimmers need one.

Maintenance: some organic/colloidal matter needs to build up (0-12 hours) on the inside of the neck to help skimmate climb... but after 2-3 days, it actually impedes skimmate collection.Clean your skimmer neck interior every couple of days for overall improved skimmate collection. Having two skimmers cleaned on alternate days for big tanks is particularly helpful.

Shall I go on?

Skimmer design. Sigh... we/I could talk for days about this. You'd think that if you spend $200+ dollars for a skimmer (even 300-500) you should get a wicked good performer, right? Well... one would think so. Alas, this is one area of the industry where the adage "good things are seldom cheap and cheap things are seldom" good actually doesn’t hold up. I would not take the majority of skimmers on the market for free.

Fortunately... on message boards like this with a lot of skilled aquarists, it’s not hard to see/read (archives) recommendations for quite a few good performing skimmers. My only beef with some of the better skimmers is that they are poor values (weak bang for the buck... or in otherwords: overengineered/overpriced).

Will you get twice the skimmate production/quantity out of the best $800 skimmer as you will out of the best $400 skimmer. Nope... not even close. There are some fab skimmers for $200-400... and I have yet to see a skimmer over $500 that was a good value.

Last of all... there is just daily tweaking and tuning and learning your skimmer. That is something we need to see more of... workshops at local clubs showing people how to install and maintain their skimmers. Dialing needle (air) valves on venturis (boosting the air injection)... showing the difference (benefit) of a gate valve on the outflow versus the inflow side.

I do hope I've given you some food for thought though.

FWIW... the best skimmers I've even used (total skimmate volume/quality) were those DIY Nilsen style skimmers. But admittedly, they are large, ugly, noisy and more (daily) work to keep going.

Nowadays... I am quite content with an ASM, Euro-Reef, or Aqua C skimmer. There are plenty of other great skimmers out there. I just figured I'd save somebody the keystrokes to type what brands I thought were good values

with kind regards to all,

Anthony

[micki]

Good Article!  Glad to see ASM is on the good list! 

[aquavista99]

I recently put Anthony Calfo's article to the test by experimenting with two Aqua C EV skimmers on two different systems/setups. The first skimmer, an Aqua C EV-240 was externally installed to a sump where the skimmer's pump was placed directly in the  path of raw water which flowed straight from the aquarium into the skimmer via a 40 gallon breeder sump.  This setup requires me to change the collection cup twice daily and yields very dark skimmate, which overflows into a five gallon bucket if I do not restrict the output, otherwise it would produce even more dark skimmate daily .

The second skimmer, an Aqua C EV 180, was placed in a 30 gallon open sump (i.e., not fed raw water) and produced considerably less skimmate until I altered my sump design and moved the skimmer's pump directly in the path of the raw water which flowed straight  from the main tank.  Now this skimmer is yielding lots of dark skimmate as well. Some skimmers can perform well in open sumps... but most do not.

Anthony Calfo is right!!! Anything less than raw water overflowed or fed straight into your skimmer is a compromise. As for his recommended skimmers, I don't think he is knocking the big boys, like Deltec or Bubble King, but rather stating the obvious, i.e., you get more value for your money if you select the types of skimmers he recommends. But if you have an additional $4000 laying around the house, by all means, you will get better performance out of a Deltec or Bubble King skimmer, but maybe not enough to justify paying an additional $3500 for a few more ounces of skimmate daily.

[rmstevensiii]

Very good article.  I guess I need to revisit my setup.  How do most here have their skimmers setup?  Mine is currently running in a fairly high-flow, open 20g sump/fuge.  My skimmer pump sits at the bottom of the sump, right next to my return pump and my skimmer return line and overflow from the main tank, both drain into the fuge end of the sump.  The actual skimmer is sitting outside of the sump.  Per the article, this is not the most efficent setup, so I gues I have some work to do.

[scott wilson]

Very good article.  I guess I need to revisit my setup.  How do most here have their skimmers setup?  Mine is currently running in a fairly high-flow, open 20g sump/fuge.  My skimmer pump sits at the bottom of the sump, right next to my return pump and my skimmer return line and overflow from the main tank, both drain into the fuge end of the sump.  The actual skimmer is sitting outside of the sump.  Per the article, this is not the most efficent setup, so I gues I have some work to do.

So you run water from the tank through the fug and then the skimmer and back thought the fuge.  You have a circle there.  You really want your fug after your skimmer or as a separate tank totally.  Yes I try and run all of my raw water around the skimmer pump.  My open sumps have plastic bins in them that collect the drain water and send it past the intake of the skimmer pump.

Scott

[rmstevensiii]

Scott,

Thanks for your feedback.

In a perfect world, I'd like to change the sump/fuge around so that water from the tank drains into the skimmer section on the far left side of the sump with the return pump in a seperate section in the middle of the sump, between the skimmer and fuge.  I'd like to slow the flow-rate thru the fuge and skim from the raw tank water. 

In the real world, I'm limited by the space I have beneath the stand, and the dimensions of the AGA 20 gal tank that I'm using for a sump/fuge.  If I break it up into 3 seperate sections, I'm not sure that I'll have enough room in the fuge section to make the fuge worthwhile.  If I can find a larger std tank, I'd like to try to move the external tank into the sump, as mentioned above and tee off the return line to feed a seperate fuge. 

What is the largest sized std tank that will fit thru the double doors of a std 75 gal stand?

With the fuge, as-is, my Mandarin is fat and happy, no doubt, due to the large number of pods and other critters living there, which make there way into the main tank. 

[aquavista99]

The largest sump you can fit under a 75 gallon is a 30 gallon, long. However, you would need to install the sump first without water in the 75 gallon because I don't think it will fit through your doors. It may fit through the back of your stand. It really depends on the clearance with your existing stand.

[rmstevensiii]

My stand is backed up to a wall, so there's no access from the rear.  Guess I'm stuck for now. 

[scott wilson]

you could do 2 smaller tanks and drill them and plumb together.  But I am not sure if you will get much benifit from that.  The best thing you could do is have the fug a taller tank.  and the sump long.  GET out the graph paper and start your floor planing. 

P.S.  do you need a third door?  add one on the end and you ca get a big tank inthere. BUT check your support structure before dooing so.

[ohioreef]

I was able to squeeze a 30g tank through my doors on my stand. My skimmer sits in the same chamber as where the overflow spills into so I should be getting raw water into my skimmer.

[rmstevensiii]

Hmm... 30 gal.  Do you have any pics?

[aquavista99]

I recently put Anthony Calfo's article to the test by experimenting with two Aqua C EV skimmers on two different systems/setups. The first skimmer, an Aqua C EV-240 was externally installed to a sump where the skimmer's pump was placed directly in the  path of raw water which flowed straight from the aquarium into the skimmer via a 40 gallon breeder sump.  This setup requires me to change the collection cup twice daily and yields very dark skimmate, which overflows into a five gallon bucket if I do not restrict the output, otherwise it would produce even more dark skimmate daily .

Here are some pictures of the above setup.

[attachment deleted by admin]

[ohioreef]

Go to: http://www.ohioreef.com/filtration.html for pics of my set-up.