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The velocity at which the coral spin thru the water will surely stripe any living tissue off it.
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That's why I asked how fast it spun.....
Can't we gear it down or something?
Lets McGyver something together....
Can't we gear it down or something?
Lets McGyver something together....
I dont have any pics but will try to get some tomorrow if I remember to bring a camera to work.
Hard to say how fast it is spinning. I would gues about 1000 RPM. If we can rotate the coral than there would be no need for water movement. I would like to try that when I go to the moon. Lets do that. I had a rotating fish tank a few years ago and the coral grew normally but the tank went very slow.
Hard to say how fast it is spinning. I would gues about 1000 RPM. If we can rotate the coral than there would be no need for water movement. I would like to try that when I go to the moon. Lets do that. I had a rotating fish tank a few years ago and the coral grew normally but the tank went very slow.
It doesn't even come close to enough torque to do something like that. Bryan and his ideas.... 
The model I posted spins up to 1500 rpm. It's tricky attaching anything to the bar because as soon as you do it throws off the weight balance of it. Then you get a rattling sound.
The model I posted spins up to 1500 rpm. It's tricky attaching anything to the bar because as soon as you do it throws off the weight balance of it. Then you get a rattling sound.
Matt, we have 4 mag. plate stations at my facility. You could have 4 impellars. Our units are geared for lower velocity though, .001rpm to 100rpm We have larger/faster ones as well. The real trick, is getting one with out any internal moving parts. Most have a "spinner" inside them that creates the motion.
We have larger/faster ones as well. The real trick, is getting one with out any internal moving parts. Most have a "spinner" inside them that creates the motion.GreshamH":d3cbcpjl said:Matt, we have 4 mag. plate stations at my facility. You could have 4 impellars. Our units are geared for lower velocity though, .001rpm to 100rpm
And heat. Click that link.
No moving parts. I'm guessing (you're the electronics whiz) that it sends timed electric pulses to create a spinning magnetic field (???). Make sense?
>...And [no] heat.
It always send some pain up my neck whenever people says no heat when moving/stirring/pumping water... but I guess I am a nit picker.
The one with spinner usually works better in low RPM. For the all-electronic version, you need to have 6 poles to work well, but maybe they have better magnet nowadays. :?
It always send some pain up my neck whenever people says no heat when moving/stirring/pumping water... but I guess I am a nit picker.
The one with spinner usually works better in low RPM. For the all-electronic version, you need to have 6 poles to work well, but maybe they have better magnet nowadays. :?
I will always remember the high-school physics experiment where our teacher made us take a beaker of room temperature water and a glass stirrer and hand stir the thing (vigorously) for 5 minutes straight (try it some time, it sucks) We took temperature readings at the beginning and at the end.
Water movement generates heat from friction against the container walls, the stirring implement, etc.
Apparently, I did not pay so much attention in english class... 3rd edit for spelling.... :?
Water movement generates heat from friction against the container walls, the stirring implement, etc.
Apparently, I did not pay so much attention in english class... 3rd edit for spelling.... :?
Teflon is fine for use in a tank, its actually one of the least reactive of the plastics and we use it for sampling, etc all the time (only one compound leaches from it and its highly resistant to everything).
I imagine, that if you get a single grain of sand under that stir bar, its going to scratch the hell out of your tank... what I would suggest would be a small square of flat teflon between the glass and the stir bar to keep grinding to a minimum (and noise).
Placing a stir bar on the side of a tank... I dunno how well that would work as far as water movement. A prop pushes water forward. A stir bar brute forces water to the sides. That means you'd have a semi-circular movement of water over that pane of glass, not really moving across the tank.
Interesting idea nonetheless... lets see it tried out.
I imagine, that if you get a single grain of sand under that stir bar, its going to scratch the hell out of your tank... what I would suggest would be a small square of flat teflon between the glass and the stir bar to keep grinding to a minimum (and noise).
Placing a stir bar on the side of a tank... I dunno how well that would work as far as water movement. A prop pushes water forward. A stir bar brute forces water to the sides. That means you'd have a semi-circular movement of water over that pane of glass, not really moving across the tank.
Interesting idea nonetheless... lets see it tried out.
cknowlto, you know I usually discount the techicality / creditability of anybody/any company that try to say their pump add no heat to the aquarium. It usually means that they are more of a salesman than engineer or scientist. Not that there is anything wrong with being a salesman, but trying to pass off as someone else is just misleading.
seven ephors":n3cgg217 said:
You are right that mechanical energy in a closed system utlimately results in heat, however you're not portraying the whole picture...
All motors/pumps have a certain efficiency level at which they operate, and I'm not talking about watts-in vs. flow out. I'm talking about efficiency as a percentage in terms of power-in vs. power-out.
I'm going to use a simple to follow example: an AC and DC motor both drawing 100 watts.
Let's say that the AC motor has an efficiency of 60% and that the DC motor has an efficiency of about 70% (these numbers are relatively accurate but of course will vary from motor to motor depending on technology, quality, etc). This means that in the case of the AC motor, 60% of the 100watts is being converted to mechanical energy and 40% is dissipated as heat. If this AC motor is a 100w powerhead, such as a mag pump or something, that basically means that 40w of energy are being added to the aquarium as heat dissipated to the water directly, and the other 60w are being added as mechanical energy.
In the case of the DC motor, at 100watts and 70% efficiency, 70w of energy is being added as mechanical energy, and 30w is being dissipated directly into the water as heat.
Now to pull this back to the whole inside the tank versus outside the tank thing...
Firstly, in an external drive pump, YOU ARE REMOVING HEAT FROM THE AQUARIUM. The heat you are removing is the input energy which is not being outputted as mechanical energy. This is the 40w and 30w in the example above. This is fact, it is not sales hype, it is not a lie. The rest of the energy is being converted into mechanical energy which is added to the aquarium.
Secondly, the amount of heat an externally driven pump will add to an aquarium depends on how well its designed to isolate the heat generated by the motor from the water. Many external magnetic drive and direct drive pumps will actually heat the water a bit just by nature of the motor flowing heat through the magnets/metal drive shaft (good conductors) and into the water. In the case of a pump such as the this magnetic stirrer or the vortech, little heat is added in this sense because glass is a good insulator, and thus prevents heat from the driving magnets passing through the glass and into the water.
I hope everyone was able to follow me here.
I follow your logic, Timbo, and knucklehead follow my logic too.
To be fair, I am a bit of nit picking here. FWIW, I have no problem if they say a device does not add heat directly, or it add little heat, or it add almost no heat.
On the humorous note, let me quote you...
This sounds like my wife who often say that she save me hundreds of dollars by buying clothing in Macy's during sale events. (BTW, she makes more money than I do, and I use the similar statement when I come back from LFS too.)
To be fair, I am a bit of nit picking here. FWIW, I have no problem if they say a device does not add heat directly, or it add little heat, or it add almost no heat.
On the humorous note, let me quote you...
This sounds like my wife who often say that she save me hundreds of dollars by buying clothing in Macy's during sale events. (BTW, she makes more money than I do, and I use the similar statement when I come back from LFS too.)
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