Waterchange Temperature

RiaanP

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How do you get the water for a water change to be exact the same temp? I got about 150 liters system, and one 20L can is enough of a water change per week. But how do I get it the same temp?
 

Tobes

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I have a make up drum with a heater and a circulation pump in. I first heat the RO, then add the salt and "age" it for a day or two while being circulated. I make sure that my heater is set in such a way that the temp is the same as my main tank - and I double check with the same thermometer. I also match the salinity with a refractometer ;)
On a big system of 1000litres and above it's not so very critical, but on a smaller one I'd advise to match the parameters as the fish can get white spot or osmotic shock from different salt levels ;)
 
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I have never equalised my water. I have done the calculations and you would need a HUGE temperatures difference for it make any difference on your tank, unless you were doing WC bigger than 50%.

Temp. Sum:

50L @ 30°C is mixed with 450L @ 25°C, the 50L is 10% of the total volume (50 +450), so it's temperature effect will also be 10% iE: 0.5°C (10% of 5°C - difference between the 2 temps)

I know there maybe other factors involved with water temperature.

If I am calculating this right a normal type WC for me 10%, would need to be over 20°C difference, before I would have a significant temp. swing.

My 2c
 

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True to a certain degree Warr. Depends where the new water is introduced into the tank. If you put it gradually in the sump and let it mix a bit before being pumped through I would say yes, you're right it doesn't matter that much. But you get setups that it is just easier to add the water directly in the main display, and then I would say rather make sure all parameters are the same. I mean imagine the temp differs with 5-10deg and at that moment when you pour the new water a lovely fishy or invert is curious and come directly into the stream. Some sensitive fish or inverts cannot handle such a big difference in temp. Just my opinion :wave2:

even worse if the salinity is not the same...
 

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SG is affected by temp, so to ensure you are adding water at the correct SG (i.e. the same as in your tank) then you MUST equalise the temps, which is done using a container and a heater and a powerhead to circulate, when the temps are the same, check the SG levels (adjust if necessary) then perform the water change.
 
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SG is affected by temp, so to ensure you are adding water at the correct SG (i.e. the same as in your tank) then you MUST equalise the temps, which is done using a container and a heater and a powerhead to circulate, when the temps are the same, check the SG levels (adjust if necessary) then perform the water change.
Ok, so how do you equalise, when the tank temp is 25 and the WC temp is 27 ?
 

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SG is affected by temp, so to ensure you are adding water at the correct SG (i.e. the same as in your tank) then you MUST equalise the temps, which is done using a container and a heater and a powerhead to circulate, when the temps are the same, check the SG levels (adjust if necessary) then perform the water change.
This is exactly what I'm doing ;)
 

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Thank you Warr. Working in percentages I could not understand the 2 previous replies. 10% will have same effect on 100L, 1000L or the ocean.
Then on this calculation the salt level should change will also be so slight, that why bother.

Also doing 10% on a 1000L tank, I have to get 5 20L drums, with 5 heaters, testing them all???? or 1 bigger drum with 100L in there with one heater parked in the middle of the living room for a day or two. Definitly no nooky from my wife for a couple of days...

So if the water temp feels with your hand close enough, just go ahead.
 

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Ok, so how do you equalise, when the tank temp is 25 and the WC temp is 27 ?
Do you have this problem? i suspect not, but hell, i'll play:p

Either cool one side down, or heat the other side up (or a bit of both) not difficult really.
 
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Do you have this problem? i suspect not, but hell, i'll play:p

Either cool one side down, or heat the other side up (or a bit of both) not difficult really.
But heating the tank, wouldn't that cause problems for the inmates ?
 
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I normally get the water up to temp by spinning it for a couple of hours with a powerfull pump, then do the water change to the first chamber of my sump. This is the return chamber from the DT so by the time it has gone through the various chambers, DSB and pumped back into the DT it has been mixed well with the rest of the water. Also, don't be too hasty in pumping the new water to your system. IMO siphoning it slowly instead of using a powerhead or pump gives the water time to mix.
 
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So if the water temp feels with your hand close enough, just go ahead.
That's what I have been doing for the last year.

My water temp out my RO unit is between 26-27 degrees at the moment, how the hell would I keep 50 - 100L of water at 25 degrees for 24 hours well mixing.

It just didn't make sense. So after doing a 50L WC, checked the parameters and check my inmates, and 3000L later no probs.

I would say that this is all cool at differences that are small, if the differences were really huge, then the main tank would take longer to re-adjust the entire volume, and durng this process harm the inmates
 

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Thank you Warr. Working in percentages I could not understand the 2 previous replies. 10% will have same effect on 100L, 1000L or the ocean.
Then on this calculation the salt level should change will also be so slight, that why bother.

Also doing 10% on a 1000L tank, I have to get 5 20L drums, with 5 heaters, testing them all???? or 1 bigger drum with 100L in there with one heater parked in the middle of the living room for a day or two. Definitly no nooky from my wife for a couple of days...

So if the water temp feels with your hand close enough, just go ahead.
I don't even trust some thermometers, and you trust your hand? There is no way you'll feel the diffs of 5deg. Like Mike said, it is more about the SG because that gets affected. Read in post #5 my reason why I keep the temps the same. If you stick to how you do it, then why did you start this thread? :whistling:
 

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OK take 500L tank for example.
Tank at 25C
remove 50L
Leftover 450L at 25C. Multiply 450*25=11250
50 WC water at 30C. Multiply 50*30=1500
Add values 11250+1500=12750
Divide by total volume 500L = 25.5C

Thus doing a 10% water change with water that is 5c too warm. Results in a .5 increase in temparature.

Why break my head.
 

RiaanP

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Tobes I started it because somebody mentioned that the SW waterchange must be equal etc... And I though that I might plan in my future tank a 50-60L reservior to keep the water out of the way for 2 or 3 days before using it. That is why.

Might be good if you mixed your own SW or just got new SW from LFS to still keep it a couple of days, but is it really needed in a reservior? The reservior will run alongside the sump (if there is space) so after 3 days the temp must be as close as possible, without extra heaters etc.
But now it seems that just walking in with 3 cans 20L SW is easier. And reservior is a nice to have / not needed
 

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OK take 500L tank for example.
Tank at 25C
remove 50L
Leftover 450L at 25C. Multiply 450*25=11250
50 WC water at 30C. Multiply 50*30=1500
Add values 11250+1500=12750
Divide by total volume 500L = 25.5C

Thus doing a 10% water change with water that is 5c too warm. Results in a .5 increase in temparature.

Why break my head.
But what about the change in Salinity due to mixing salt at 30c?
 

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