Water change temp. What do you do?

Jedi1199 · May 4, 2022

Today is water change day for my 55g. I drained out about 30% of the water and was all set to start refilling the tank when I noticed... "This fresh water feels cold". Quick run to the kitchen to grab the handy dandy digital instant read thermometer and what do you know.. the fresh water is actually 4 full degrees colder than the tank.

I am bringing it up to temp now, (no big deal, simply boil a gallon or so and add it back to the fresh water can).

I always try to match the temps as closely as possible when adding water to my tanks. What do you all do? Are you like me, matching to the closest 10th degree, or do you just use whatever temp you have on hand?

I'm curious to see what everyone else does.

Floyd- · May 4, 2022

As long as its kinda close I dont care. Maybe 2 degrees

ZoWhat · May 4, 2022

Heat it up MacGyver

blaxsun · May 4, 2022

For the odd water change I perform I take the water out of the sump and return it the same. The heaters are in the sump, so with all the pumps and wavemakers the temperature maybe only drop 0.5 F. For larger water changes I throw a small heater in the pails about an hour prior.

92Miata · May 4, 2022

30% at 4 degrees means a change of about a degree in the tank. Just don't worry about it.

Constant temperature is not in any way beneficial to corals, doesn't mimic their environment at all, and there's significant evidence that corals kept at consistent temps are more succeptible to damage in temperature events.

My water barrel is in the garage. I don't worry about temp unless its going to significantly change the temperature of the tank. iE, a drop of 10 degrees in the tank.

When I do 10-15% changes in the winter, I'm often using salt water thats less than 50 degrees.

dvgyfresh · May 4, 2022

Temperature change in water change would just be like a warm/ cold current in the ocean. It can actually be beneficial, when I did a cold water change it caused my anemones to spawn

All_talk · May 4, 2022

I keep fresh saltwater on hand, there is a heater in the container, but its always a little different than the tank, I don't sweat it.

mudbugmike · May 4, 2022

Same as others. I don’t bother unless temp is way off ( winter)

EeyoreIsMySpiritAnimal · May 6, 2022

While I agree that a temporary temperature swing from a water change is nothing to worry about, remember that many instruments we use to measure salinity are calibrated at specific temperatures. If the instrument you use does not have built in temperature correction (or only corrects for a limited temp range), the salinity of your new water may be off...
Here's a nice article by Randy that explains it.

http://reefkeeping.com/issues/2004-07/rhf/index.php

ReefRondo · May 6, 2022

I do all of my water changes automatically with my Apex and a DOS throughout the night slowly therefore temperature doesn’t matter at all as it is happening so gradually. However I do keep my salt water storage tank at 25 degrees for those massive emergency water changes that DO happen from time to time. I got caught out once and never again.

Big Smelly fish · May 6, 2022

I personally never check temperature of water change water. Never a problem. A few degrees not going to hurt anything in my opinion.

DHill6 · May 6, 2022

Jedi1199 said:
Today is water change day for my 55g. I drained out about 30% of the water and was all set to start refilling the tank when I noticed... "This fresh water feels cold". Quick run to the kitchen to grab the handy dandy digital instant read thermometer and what do you know.. the fresh water is actually 4 full degrees colder than the tank.

I am bringing it up to temp now, (no big deal, simply boil a gallon or so and add it back to the fresh water can).

I always try to match the temps as closely as possible when adding water to my tanks. What do you all do? Are you like me, matching to the closest 10th degree, or do you just use whatever temp you have on hand?

I'm curious to see what everyone else does.

Temp match, I make the water a day ahead and heater in the bucket.

Freenow54 · May 6, 2022

Jedi1199 said:
Today is water change day for my 55g. I drained out about 30% of the water and was all set to start refilling the tank when I noticed... "This fresh water feels cold". Quick run to the kitchen to grab the handy dandy digital instant read thermometer and what do you know.. the fresh water is actually 4 full degrees colder than the tank.

I am bringing it up to temp now, (no big deal, simply boil a gallon or so and add it back to the fresh water can).

I always try to match the temps as closely as possible when adding water to my tanks. What do you all do? Are you like me, matching to the closest 10th degree, or do you just use whatever temp you have on hand?

I'm curious to see what everyone else does.

Water change I like the temp as close as possible that's why heaters in my container. Not as fussy with top up temp same as home

damsels are not mean · May 6, 2022

I used to heat my water change water, then I forgot one day. I was like "do I even have to heat it?". Did the math and room temperature water would only really lower the temp by a degree or 2. I don't keep temp that stable in my tank anyways.

fish farmer · May 6, 2022

I keep my makeup saltwater heated winter or summer. I don't see an issue with a degree or two. My mixing station is in the basement so I can get 50's or lower in the winter.

I will always heat my WC water and this is the reason why. Several weeks ago before my extended vacation I was doing the obligatory WC, check equipment, etc. I was rushing or just preoccupied and filled my WC bucket with fresh RO/DI water, the vessel is next to my salt vessel. I noticed my WC water was really cold when I was adding it to the sump, luckily I didn't pump much into my tank.

EricR · May 15, 2022

Erin1971Texas said:
While I agree that a temporary temperature swing from a water change is nothing to worry about, remember that many instruments we use to measure salinity are calibrated at specific temperatures. If the instrument you use does not have built in temperature correction (or only corrects for a limited temp range), the salinity of your new water may be off...
Here's a nice article by Randy that explains it.

http://reefkeeping.com/issues/2004-07/rhf/index.php

Same here -- I heat my mix only so I trust (more) my salinity measurement,,, not concerned with temp difference from tank (assuming reasonable size water change and not near-freezing new water).

i cant think · May 15, 2022

I have to bring salinity up so I bring temperature up aswell just in case. Although, sometimes I do wish I could freeze my tank especially recently (Darn Eunice species in my nano).

jabberwock · Jul 16, 2022

If someone is having keeping tank temp down, would an intentional REFRIGERATED small water change be helpful? No lid, fan blowing on water, 104 degrees outside...