Adventures in skimming

[blainep]

For those that have been following my 'Dipping a toe' thread, now that the Nano tank is essentially finished (Is a tank ever really finished ?), I've been researching a new skimmer for my 50 gallon tank.

After spending a few days searching and researching I decided to put my DIY skills to work and see if I could really see what makes a good skimmer.

The results so far have been ..... well, interesting.

I didn't want to go whole hog yet and spend more than I would on a high end skimmer by the time I was done, so I started looking around.

It appears that a 2 liter soda bottle has nearly the perfect neck for a skimmer, so with a little rooting around in boxes of goodies I found a few more bits and decided to see how much damage I could do.

Skimmer V1.0

A 2 liter pop bottle, holes drilled into the bottom for water to escape from, a small power head mounted to the side of the bottle and a limewood air diffuser in the bottom.
The collection cup was made of the top half of a water bottle with a 3/4 inch PVC slip connector and a short piece of 1/2 inch flexible PVC jammed in for a riser tube.

The result looked like this.

The collection cup
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The skimmer body
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Installed and running,
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My initial response was disappointment, the Limewood wasn't producing as many bubbles as I would have hoped, some of the bubbles were escaping the body of the skimmer thru the holes I cut in it to put in the airline and diffuser.
Also, the powerhead had a small air venturi that wasn't pulling any air.

I decided it was time to make dinner and ponder Skimmer V1.1.

Upon returning from dinner, I was pleasantly surprised to find that the collection cup had about a 1/2 ounce of tea coloured skimmate in it.

That really got the wheels turning, if I could make a skimmer that crappy and have it still work, what if I put another 15 minutes thought and 1/2 hours work into it, I could be a skimmer GOD !

Skimmer V1.1 died on the operating table and could not be resuscitated. Poor thing, died before it was born.

With that, I stepped down from the skimmer GOD pedestal and got the brain in gear again.

[blainep]

I needed to fix the venturi on the pump, I assumed the bottle was being slightly pressurized and that was killing the venturi effect. I also needed more micro bubbles in the skimmer body and no open holes in the skimmer body, no matter how small they were.
All that and maintain what little structural integrity the pop bottle had.

Skimmer V1.2

First to tackle the problem of fitting my meathook (hand) into the the skimmer body without turning the bottle into a useless floppy piece of plastic.

The best answer that seemed to work.

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Next, not enough micro bubbles.

I could feel when I removed the air pump hose that the air pump was putting out lots more air than was being diffused by the limewood. The solution -

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Next, mount the powerhead and attach an airline to the venturi. I put it on upside down in hopes of pushing water up into the vortex of microbubbles.

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Skimmer V1.2 Ready for action !
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[blainep]

The initial results of Skimmer V1.2.

The venturi is still not working. I know it's not plugged (yes, I wrapped my lips around it and blew thru it !)and there can't be any pressure in the skimmer body with the big hole in the bottom.
Maybe it's just old and feeble.

Other wise, looking not to bad.

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A good froth of microbubbles and the powerhead is swirling them around really well.
A few bubbles are starting to climb the riser tube already.

[CACAdmin]

You've missed you true calling, Blaine. You should have been an inventor! Lookin' Good!

[blainep]

Results at 1 hour.

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It's way to wet, but it is tea coloured skimmate.

Thoughts so far.

A longer skimmer body would be ideal, longer contact time with the foam would produce better efficiency.
A better mount, the poor little suction cups on the powerhead just aren't strong enough.
A working venturi would be nice, but I have an idea for that, I'll incorporate it in V1.3.
A way to change the water height in the skimmer body to produce thicker/darker skimmate.

If anyone has any input, feel free to chime in.

This is just an experiment to see if building my own skimmer is really feasible.

So far, it's cost me 60 cents in bottle deposits lost. :laugh:

[blainep]

A little more time and ......

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The cup is going to overflow soon, but thankfully, I was smart enough to make the cup easily removed.

All in all, considering there is no way this little skimmer is 'broken in' yet. Not bad.

[blainep]

You've missed you true calling, Blaine. You should have been an inventor! Lookin' Good!

Thanks Jay, although I don't know if I'd call it 'looking good'

If I decide to continue this adventure, I'm going to have to bone up on my 'make it pretty' skills. :laugh:

[CACAdmin]

Functionality comes first... you can work on the comestics of it later.

[blainep]

Day 2

Back at again today, I started by pulling out lastnights skimmer and beginning the building of the next skimmer incarnation.

A taller skimmer.

I cut the top off one pop bottle and the bottom off another. With a little wiggling, they slid together to create a long 2 liter pop bottle.

I had to go out, so I stopped at Rona and picked up a couple extra fittings.

The results,

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I made a nicer lift tube and collection cup, but alas, it was a failure as well. The reason, the lift (or riser) tube must be smooth for the bubbles to travel up.

A little head scratching came up with another idea, less pretty, but effective.

The next challenge was to get more nasty stuff and less water in the collection cup.

By sliding the 2 halves of the skimmer body up, I got the neck of the bottle to stand about 2 inches out of the water. A little playing with the length of the riser tube and I appear to have a working skimmer.

The foam coming out the top is fairly dry and has a nice brown colour to it.

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The skimmate in the cup is pretty thin looking, but that's because I haven't dumped it since I got the height set.

So, what have I learned from this ?

- A DIY pop bottle skimmer works, works quite well actually.
- Would I use this as a full time skimmer, probably not as it is, some more work and this might be fine. It ain't pretty, but it works.
- I would use it as a backup skimmer or in a QT tank, without a second thought though.
- If you're on a super tight budget, this will work (but if you're on a super tight budget, don't try a marine tank ! It's a money pit !).

What would make this skimmer better ?

- A better neck/cup design.
- A slightly stronger powerhead with a needle wheel or venturi.

Costs ?

- I have about $5.00 invested in this skimmer, but I had most of the stuff hanging around already.
- If you seriously wanted to build one, the materials list ...

2 - 2 liter pop bottles.
1 - 500 ml. pop bottle.
1 - 10 -12 inch piece of 1/2 inch PVC pipe or hose.
One or two Limewood air diffusers.
A good air pump
A small powerhead.
Air line tubing
Zip ties.
Electrical tape ( to seal the collection cup to the pipe, do not expose to the tank water)

Tools -
A sharp boxcutter knife.
A hand saw, if you use pipe instead of hose.
Side cutters are nice for cutting Zip ties.

I'll keep this updated for a while, I'm going to run this skimmer while my new skimmer is on order.
I'm interested to see how the skimmate looks now that I have it adjusted fairly well.

I think I might try to build a skimmer for the Nano tank as well, the one that's on there now just ain't doing the job well at all.

[blainep]

A couple of hours have passed and the skimmate in the cup .....

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is getting darker.

That means more gunk, less water.

I've now dumped the cup so I can see what the skimmate really looks like. By tomorrow, if all works as planned, there should be a nice dark, stinky layer off goo in the cup.

[CACAdmin]

OK... we'll wait for tomorrow for a picture of dark, stinky goo. :laugh:

[blainep]

OK... we'll wait for tomorrow for a picture of dark, stinky goo. :laugh:

Ask and you shall receive !

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[blainep]

And today, looking even more like dry skimmate.

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Not bad at all.

[CACAdmin]

Looks like a success to me. :yes:

[blainep]

Looks like a success to me. :yes:

I would agree.

I mentioned earlier that I would hesitate to use it 24/7/365, but only because of the flimsiness of the body, but it shows that you don't need to spend a lot to get a good skimmer, or if you have a lousy skimmer, some simple mods could make it a good one.

Skimmer shopping can be quite frustrating, much as any internet research can be, 12 reviews of a product will result in 12 different opinions.

That was also part of the reason for this experiment, to try and get an idea of what makes a good skimmer good and a lousy one lousy.