Hyrdrometer....

Discussion in 'Tank Talk' started by Armstrong, Aug 8, 2003.

  1. Armstrong

    Armstrong Vampyroteuthis Registered

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    Ok I know what a Hyrdrometer is, but I want to know what it MUST read on the hyrdrometer for an octopus.

    Like for example the PH level for an octopus must be in between 7.9 to 8.2 right?

    well what level should the Hydrometer be for the octopus just so I know.
    Thank u guys for always supporting me wit this. :wink:
     
  2. Colin

    Colin Colossal Squid Supporter

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    that is a very important question...

    Its important to make sure that the water is full strength sea water... many people keep the SG on their aquariums low to prevent parasites on their fish BUT as we have an invert and one with no exoskeleton, we have to keep the water at about 1.026 and regular top ups due to evaporation with fresh RO water may be needed every few days to keep this
     
  3. Armstrong

    Armstrong Vampyroteuthis Registered

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    Ok im glad I asked but one more thing.

    You know how in temperature water in order to bring down the temperater u would use a chiller right? Amd to bring UP the temp. u would use a heater right?

    Well on a hyydrometer how would u change the levels in order to make it say 1.026?

    ThanX!
     
  4. rrtanton

    rrtanton Vampyroteuthis Registered

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    If I may (not to steal Colin's thunder...)

    Need to raise SG--add saltwater.
    Need to lower SG--add freshwater and, if necessary, take saltwater out of tank

    Your hydrometer's measuring Specific Gravity, which is basically the same as salinity (technically it's not but I won't launch into THAT...besides, I don't think I understand the differences fully myself, either! :bonk: ) In other words, it indirectly tells you how much of your tank's water is dissolved salts. Higher means more salts per milliliter (or gallon, or however you want to measure it) lower means less salts. So, to raise the SG, you need to add salt to the tank. Not directly! You need to completely dissolve it in some water in a bucket beforehand. Generally, you add saltwater to the tank at the same concentration you want the tank to be. If you need to boost the SG, you just add saltwater instead of freshwater when you top off the tank. As water evaporates, it leaves salt behind, so this method will gradually increase the tank's total salt content.

    By the same token, if you need to lower SG, you can add just straight RO freshwater. That will dilute the tank and lower SG, but it won't actually take salt OUT of the tank. If you have a too-high SG even when the tank is full, then you need to remove some saltwater and replace it with freshwater. Generally, I try to keep my tank's salt levels constant, replacing only as much as I take out, and adjust the SG as necessary with freshwater.

    rusty
     
  5. Armstrong

    Armstrong Vampyroteuthis Registered

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    THANK YOU SO MUCH FOR EXPLAINING TO ME!
    I will look forward to getting a hyrdrometer.
    But it seriously sounds like hyrdrometer is the same thing as salinity.
    I think mabye the difference is that hyrdrometer measures the gravity, while slainity measures salt.
     
  6. Armstrong

    Armstrong Vampyroteuthis Registered

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    I type way too fast when I post that's why I spell it wrong, but here's the correct spelling: Hydrometer. There u have it, lol.
     
  7. Colin

    Colin Colossal Squid Supporter

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    thanks very much Rusty :) :) :)

    On a separate note i dont think we should be arguing about typing mistakes on a keyboard as we all do it
     
  8. Armstrong

    Armstrong Vampyroteuthis Registered

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    you got that right.
     
  9. rrtanton

    rrtanton Vampyroteuthis Registered

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    Typnig msitakes? Whta rae you tlaknig abotu? :heee:

    I can try to clarify a bit about hydrometers, it is more that they're measuring "gravity" and not salinity...following are some details I was able to recall from college and glean from a bit of web-searching...my apologies if I've misapplied some of this.

    :grad: Your standard swingarm hydrometer doesn't measure salinity directly. It's measuring specific gravity, which is the density of something as compared to the density of pure water. Thus, your saltwater at a SG of 1.025 is, I THINK, 1.025 times as dense as pure water. Your swingarm floats up higher in this solution to indicate the level because the same object will float higher in a denser solution. That's related to displacement and the density of the object itself. Some metal objects sink readily in water but will float in other liquids.

    This method should work for other things as well. I believe battery-acid-strength meters (the sort of things that have little balls floating in them) work the same way. You could probably mix up a solution of sugarwater and see the same response in the hydrometer. It's all about measuring density. Since all we add to our water (more or less) is salt, we can rest assured that our hydrometer's measuing how much salt is in our water.

    Optic hydrometers (refractometers) are the same story, though they measure a different thing, in this case the index of refraction of the test sample. It's a bit more complicated, but basically, water bends light, as you notice when you see a straw in a glass from the side. All transparent materials can do this. Depending on what your liquid is, it will bend light more or less. As you might guess, the amount of salt (or anything) dissolved in water affects its index, and ultimately shifts where the line appears in the refractometer. If you do any searches for refractometers, you'll note an interesting thing--they appear to be very common in the winemaking industry for checking alcohol or sugar content.

    rusty
     
  10. Armstrong

    Armstrong Vampyroteuthis Registered

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    OH, Now I get it.
     

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