Tank water evaporating? Question

Discussion in 'Freshwater Tank Equipment' started by cheesepuff, Jul 19, 2015.

  1. cheesepuffWell Known MemberMember

    My fish tank water goes down in volume noticeably every half week or so. I think i lose about 7% of my water every week or so. It's that normal? If i fill it back up does that count as a water change?
  2. TexasDomerFishlore LegendMember

    Do you have a lid on the tank?

    Filling it back up does not count as a water change. While the water evaporates, the nitrates don't, and they become more concentrated in the tank. While adding water helps dilute them (lower ppm), it doesn't remove them. Water changes do.

  3. AquaticBrandonWell Known MemberMember

    Having a lid on your tank reduces evaporation. Just adding water isn't considered a water change, it's considered toping off water.

    Sent from my iPhone using Fish Lore Aquarium Fish Forum
  4. DanB80TTSWell Known MemberMember

    Yes it's normal, as your tank doesn't have a lid it will evaporate at a faster rate.
    It would be safe just to check for any signs of a leak though around the stand and underneath.
    You could always pick up a glass lid, they are very cheap and come in most sizes, check out Amazon or drfoster&smith. They will slow down evaporation as it hits the glass it turns back into liquid and drips into the tank.
  5. cheesepuffWell Known MemberMember

    Thanks all! I'll top it off.

    Sent from my GT-I9505 using Fish Lore Aquarium Fish Forum mobile app
  6. BornThisWayBettasFishlore VIPMember

    Yeah, the water evaporates every week a lot for me too, but I agree with the above posters that the water still needs to be taken out to remove nitrates. Sadly, my aunt has a tank that she claims to only top off the water on when it gets low, not do water changes. I tried explaining to her about why water changes were so critical and she claimed that I wasn't speaking her language, so....... *sigh* I tried.
  7. JsigmoWell Known MemberMember

    People need to understand that when water evaporates, it leaves behind anything that was dissolved in it. So as you top the tank off, the concentrations of various things increase.

    Ideally, you would top aquariums off (to replenish for evaporation) only with distilled water or at least RO water. That way, you aren't increasing the concentrations of various minerals, etc.

    And you still need to do real water changes to lower the concentrations of nitrates and other wastes that are being added to the tank by the fish and their food.
  8. LiterallyHydroWell Known MemberMember

    This pretty much nailed it on the head. If you aren't doing water changes, you're leaving all those nitrates and various minerals in the tank. When water evaporates, the only thing actually evaporating is the water.
  9. cheesepuffWell Known MemberMember

    Good thing I asked!

    Sent from my GT-I9505 using Fish Lore Aquarium Fish Forum mobile app

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