Evaporation ?

Discussion in 'General Discussions and Advice' started by jagman, 2 Nov 2008.

  1. jagman

    jagman

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    Hi guys,

    Please can you tell me if we actually want evaporation to happen or not. In my mind I see it as being something that should not happen. If you have water loss due to evaporation, surely this will increase the salinity in the tank. (Not good ?)

    I am busy setting up the plumbing in the tank that Deep Blu got. If you take a 25L drum and have an inlet from the return pump into the drum and an outlet from the drum aswell, all using hosepipe type snap fittings, this will enable you to switch pumps off, remove one drum of 25L by releasing the snap connectors, and inserting the new drum of water. No mess, no fuss, and 25 L of water changed in a few minutes. The added volume of water should also help the system. Any thoughts ?

    I have noticed on the submersible pumps that thet have a venturi. Is there a reason for them ? Is the venturi used to oxigenate the water ?
     
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  3. Mike

    Mike Retired Moderator

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    Wow, bombshell questuion of the week:) is evaporation good? tricky to call it "good" but what it actually achieves is a cooling down of the tank water - as the water evaporates is does takes some of the heat out of the tank, which is needed (Especially in South Africa) a fan helps to achieve that - pointed across the top of the tank. To combat the evaporation, you will do well to employ an auto top up device, expesnive to buy but cheap to make, then top up with R/O water as the salt level or SG increases as only water, not salt, evaporates.
    To sum up, evaporation is a pain but use it and help it to cool your tank down with a fan.
     
  4. jagman

    jagman Thread Starter

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    Oh, But if you can stabilise your water temp and try eliminate evaporation ?

    I take it that RO water is basically distilled water ?
     
  5. Mike

    Mike Retired Moderator

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    R/O means reverse osmosis filtered water, distilled water is close, but you need to have water with a TDS of zero (TDS= total disolved solids) you can buy an R/O filter in your local lfs, get on with a DI filter, the importance of good water cannot be over stressed, your enjoyment of your tank can depend on it.

    I don't think you can defy the laws of physics (Cap'n - sorry Star Trek flashed before my eyes then):) evaporation - or the desire of all matter to equalise temperature between them - will happen whether we like it or not, unless you can air con your entire house to the correct temp.
     
  6. goodisor

    goodisor

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    And even then evaporation will still take place as the aircon tends to extract moisture from the air at a rapid rate and thus the tank will try to level the potential difference......you just can't get away from evaporation [​IMG]
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

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    Evaporation is absolutely GOOD ! It allows for evaporative cooling (which is a lot cheaper than running a chiller) AND it allows one to drip lime water into the system - this helps to increase pH and adds alkalinity and calcium, all essential things if you want to keep corals. Of course you must replace the evaporated water every day, using RO water as Mike has explained.

    Your idea of doing partial water changes is quite good, except that Beep Blu might find 25kg of water difficult to move. I personally just throw an old pump, connected to a long piece of hosepipe, into the sump and pump the water to my bathroom. there I let it fill a container to control the volume of water I'm throwing away, and then simply empty the container into the bath after it's full. I then use the same pump and hose to pump new salt water from a container in my study (pre-mixed a few days before...) back to the tank. Simple, and no heavy carrying...

    Hennie
     
  8. jagman

    jagman Thread Starter

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    Cool. Thanks for the answers.

    Carrying 25L around won't be Deep Blu's problem !! Thats why she married me !! :slayer:

    Will keep you posted on the setup and how effective it is...
     
  9. deep_blu

    deep_blu

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    Yeah right!! As I seem to recall this weekend i did my fair share of carrying 25L drums up & down the beach!!!
     
  10. scubaninja

    scubaninja

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    sheesh another domestic! well, i carried over 200lts this weekend up a beach incline and up stairs, so treat it as helpfull exercise but if you can treat it as a chance to practice your managerial skills:biggrin:
     
  11. JD167

    JD167

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    Jagman, a simple DIY RO top-up is easy to make. I made mine with a very small powerhead, silicon tube nozzel glued to the front of the outlet and the hole in the nozzel cut slightly bigger, attached a long airhose pipe to to it, and installed a small balast switch in the sump to switch the powerhead on and off when the water level drops. I used an old reef salt drum to hold the RO water and powerhead.
     
  12. Roy

    Roy

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    I also wondered about the venturi for oxygenation. - i ran it while cycleing my tank but closed it off when i introduced the live stock.

    any thoughts?
     
  13. jagman

    jagman Thread Starter

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    All of the tanks that I have seen do have a small amount of air being pumped into them. It stands to reason that using the venturi but turning it down does help ?
     
  14. crispin

    crispin

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    if you are good at DIY then by all means make an auto top up. But i looked rather hard and long when i was buying mine at the beginning of the year and quite frankly i couldnt match the cost of a ready made one from eco aquatics (sponsor in durbs) so I had one shipped up and it was a great little buy. You are gonna have to top up water all the time due to evaporation, to my mind having a machine to do that is a good idea:)
     
  15. crispin

    crispin

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    as to air, I actually find my skimmer quite effective at oxygenating water for me, so i aim at having zero bubbles going into display.
     
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