Question On Water Change/top-Up And Water Conditioner

[jarthel]

i think this is better explain using an example

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1. I decided to do a 50% water change on a 100L tank. Do I add the recommended dosage of water conditioner for 100L or 50L?

2. how about for water top-up? Like due to evaporation, my water level is 1cm less than normal? How much water conditioner do I need to use?
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Thank you

 

[MikeO]

If you are adding bucket-by-bucket then just put into each bucket the amount for the water in that bucket.

If you are adding it straight to the tank then add enough for the full 100L.


Not sure what you mean about question 2 - You need to add the amount for the full volume you will end up with in the tank i.e 100L if you are adding it straight to the tank.

 

[jarthel]

If you are adding bucket-by-bucket then just put into each bucket the amount for the water in that bucket.

If you are adding it straight to the tank then add enough for the full 100L.


Not sure what you mean about question 2 - You need to add the amount for the full volume you will end up with in the tank i.e 100L if you are adding it straight to the tank.

why the difference in the amount added? I wouldn't think it would matter if the water came from a bucket or a hose?

question 2 is similar to a water change except that I'm only topping up the tank because water evaporated. so the amount added isn't much.

 

[MikeO]

Because if you are adding it bucket-by-bucket then the amount you add, being enough to treat what is in the bucket, will immediately treat the volume of water in the bucket before it goes in the tank, making it safe.

If you add the treatment to the tank first and then fill the tank with untreated water, then the treatment will be diluted through the full volume of water in the tank, rather than just the amount of water in the bucket, thus meaning that you will have insufficient dilution to treat the water if you add it to the tank then fill with untreated water if you only add enough to treat the amount of new water you are putting in.



If you are just topping up by a small amount then you dont really need to treat it, but would say that if you really want to then you would be better off just treating it in a bucket and filling it that way, since it wont take very many buckets (maybe even just one or two depending on the size of your tank) and then that way you will only need a small amount.

 

[waterdrop]

The reason that you need to dose for the full tank volume when doing direct filling is not because of dilution. Its because a working tank will have hundreds of organic and inorganic compounds present in the water, unlike water straight from the tap. Some of these compounds will bind with the Sodium Thiosulfate or Hydrosulfite salts that the conditioner products use to neutralize chlorine/chloramine. These extra reactions could leave you under-dosed for the amount of chlorine/chloramine you are trying to neutralize. Note that its advisable, especially during the first year of a tank when the filter will not be fully mature, to dose these products at 1.5x to 2x the instructed amount, but do not dose over 2x if the filter is still in either a fishless or fish-in cycle.

Hobbyists with larger tanks will generally use a more concentrated conditioner to same money: Seachem Prime during the first year (because of its good reputation handling beginner problems) and perhaps a pond dechlor product after the tank has matured more than a year and a half, if one is found that calculates out to save even more money.

~~waterdrop~~