Reef Discussion

Savage Henry

Member
Feb 2, 2015
653
254
The pill or flea as they are known have a tough teflon coating.

I used them in experiments using extremely sensitive transition metal catalysts for analysis metathesis reactions for the preparation of DNA intercalators from dialkenes.

However, I have seen some stained from chemicals but in general they are unreacted. They could react with some of the indicator dyes we use.

On the other hand, if they are cheap cheap ones from China...
 
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Sean81

Member
Nov 11, 2015
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36
Sydney, South

Savage Henry

Member
Feb 2, 2015
653
254
If the magnetic stirrer hotplates I use to use was anything to go by, I would be looking at getting a variable speed stirrer because when I used to do reactions in these vials, the stirring rate was dependent on the volume in the tube. Too high a rate and low volume = splashing.

I use to start with maybe 2ml in the tube with the flea and later add more liquid. So, I would start the stirrer slowly and quicken the speed later.

The rate also depends on the size of the flea you use. Again, I'd be going for the circular bar shaped flea and not the football shaped ones as they tended to jump about more often. The long triangular ones are also good.
 

MagicJ

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Jul 11, 2011
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Hobart, Tasmania
@Savage Henry - I assume the flea is magnetic. If so, is there any need to also have magnets rotating on the fan blade? I am guessing that doing so increases the strength of the magnetic force.
 

Sam Parker

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May 6, 2013
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Geelong
I wonder if a "shaker" could be made so that the vial was gently shook left to right instead of stirred? Basically replicate what we do by hand?
 

Savage Henry

Member
Feb 2, 2015
653
254
Stirred but not shaken is the way to go. Many reasons for this.

The fleas are magnetic.

Also one of the problems with the DIY having the magnets located on the fan blades is that it would cause the flea to jump about. Much better to have a centralised magnet located directly below the flea. As I indicated above, I think a piece of metal or magnet mounted on the spindle of the fan rather than on the fan blade would serve the purpose better. I think your right in that a magnet would be better for strength.
 

Sean81

Member
Nov 11, 2015
112
36
Sydney, South
@Sean81 - what would you suggest as the ideal RPM for this application?
Mine is as slow as it can go and still be able to start rotating on the low voltage, if I used a PWM I could go slower. But the speed it goes is perfect for checking ALK with 5 ml of water which is why I made it. Works really well. I have a small LED PWM I'm going to try soon.

Also it doesn't jump around if I get the glass in the middle of the fan which will be held there with PVC soon. If you are worried about jumping you can glue the magnets closer on the fan
 

Sean81

Member
Nov 11, 2015
112
36
Sydney, South
How would one of these stirrers go keeping kalkwasser mixed? is there enough torque? If not can you make it more powerful?
With a bigger fan and stirrer would be fine. On a timer the stir at set times. GHL sell similar for that purpose. But will need a power supply
 
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MagicJ

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Jul 11, 2011
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Hobart, Tasmania
@VaultBoy - good to see you are still around :)

I was thinking of something like this to stir a micro algae culture, which would probably be on a similar size scale to a kalk reactor.

You are probably thinking of something like this - http://barraquatic.com/kalk.php

upload_2016-4-10_9-4-1.png


I have ordered some magnets/stirrer bars from China and will have a play when they arrive.
 

VaultBoy

Member
Jul 10, 2011
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Gawler, S.A.
@MagicJ Ive been lurking! I check up on you lot every couple of months ;)

I havent had a tank running for about 2 years now (I think) I gave the last of my stock to Leslie (I think) on here because Ive been dealing with a chronic back injury and hopefully having surgery to fix me up soon. I wasnt able to keep up the tank so I shut it down and now I miss it.

Im thinking of setting up a 2 - 2.5 foot tank when I'm back on my feet though but need to re learn a bunch of stuff!
 

Sam Parker

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May 6, 2013
4,802
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Geelong
It is nice feature on the GHL doser to have the stirrer plugs on the back. I assume they stir for a short time before dosing which would be so simple to do, but such a nice feature