ECFENCING

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How long does everyone wait until they use freshly mixed saltwater for a water change?

The few local reefers I've talked to let it mix overnight but can you use the new mix sooner? i.e. after it has matched the salinity and temp to your aquarium?
 

marrone

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A lot of people mix it over night some the same day. A lot has to do with how well it disolves as you want to have it well mix before you add it to your tank. If it's not mix well it can burn corals and fish once it enters your tank. A big thing is also the size of your tank. In a small tank you want to make sure it mixed very well as the impact on the system will be a lot more than in a larger tank.
 

marrone

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I usually mix mine that morning and do the change later in the evening on my reef tank. On my fish tanks since I make a very strong concentrated mixture I do it a couple of days before so it completely mixes, which most of the time it still doesn't. It also lets me get a good reading before I make the water change.
 

ECFENCING

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thx guys. I guess as long as you don't see any salt on the bottom of the bucket it would be fine. Just want to do a water change tonight. Started mixing at noon and was going to do a w/c before I went off to bed tonight 11:00. Tough to do w/c during the week when you get home from work
 

masterswimmer

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alrha said:
is there any need to heat the water while mixing if it is going to be only a small percentage of the water (i.e. <5%)?

Albert, the reason you'd want to heat it is for dissolving the salt. Salt will dissolve much quicker in water at ~ 78 degrees. Not to mention trying to keep the water at a temp relatively close to that of your tank.

ms
 

alrha

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yeah, but if it is at room temperature (say 70F) i dont see it making much of a difference... the only issue i see would be testing the salinity with a non-temp adjusted tool (such as a hydrometer) as the SG would read differently at a different temp.
personally i use a pinpoint salinity monitor which takes temp into account when calculating the salinity.
 

jhale

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I wait over night and use a strong pump to keep the water heated and promote oxygen exchange. Like cali sometimes my day turns into many days.
 

masterswimmer

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alrha said:
yeah, but if it is at room temperature (say 70F) i dont see it making much of a difference... the only issue i see would be testing the salinity with a non-temp adjusted tool (such as a hydrometer) as the SG would read differently at a different temp.
personally i use a pinpoint salinity monitor which takes temp into account when calculating the salinity.

I follow your logic, however, water is a strange creature :cat: . If it is kept within a room, it will be colder than room temperature. To be as succinct as possible, water is like a heat sink.

Water (matter) is a reservoir for energy (heat). Energy is stored in the motion of the molecules of water. As you add heat (energy) to water its temperature rises and the molecules move faster -- you're 'filling' the water up with heat. The temperature is related to how "full" of energy the water is.

The water basically keeps absorbing heat from the room but cannot reach the temperature of the room unless the room was above 212 degrees, at which point the water would change to its gaseous state.

So if you keep your room at 70 degrees, I'd guess that your reservoir of water would be in the 60 - 65 degree range.

Sorry for the less than exciting explanation :irked: .

ms
 

alrha

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masterswimmer said:
The water basically keeps absorbing heat from the room but cannot reach the temperature of the room
if the water was ABSORBING heat, or energy, from the room wouldnt that RAISE its temperature ABOVE room temperature?
I would suspect that evaporation, an endothermic reaction, is what is using the heat/energy from the water and cooling it off (much like the fans over our tanks).

either way, even if it were a few degrees cooler, how much of an effect would it have?

if I change 5g (at 65F) on my 200g tank (at 80F) my temp would be ((195*80 + 5*65) / 100) 79.625 - not really such a significant difference IMO.
 

marrone

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If you changing a small % of water a few degree below isn't going to have any effect on the tank. Even if you do a large change, and the water is cooler by a couple of degree, your not going to see a change. Also my top off water is usually colder than what in the tank and there isn't an effect.

When I do large water changes on my fish tanks I don't even worry if the water is cooler by 3-8 degrees as the impact is minimal to nothing.
 

alrha

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i agree, perhaps because i only do small water changes (simply easier as i just use a 5g bucket) it doesnt have much of an impact. those who do larger WCs, such as 25%, probably would have to be more careful to match paramaters closer.
 

marrone

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A lot also depends on the size of the tank as 25% on a small tank will have much greater effect than a 25% on a large tank. Also when most people do water changes they add the water to the sump, instead of directly to the main tank. Since most people have heavy pumps in the sump the water is probably hot there than in the main tank and by the time the water is mix and returns to the main tank the water should be heated up to the proper temperature or close enough where it shouldn't have any effect.
 

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