Tempature fluctuations with water changes

  • #1
Hello all - I have a quick question. When I do a water change my tap water right now is extremely cold due to having a slab house. It will change the overall temp of my 36G anywhere from 2-3 degrees right now when I do a 30% PWC.

Right now I have 2 goldfish in the tank so I'm not overly concerned however once I re-home them this spring I an converting my tank over to a tropical tank and I know water temp parameters are much more important.

I am going to pick up a couple more buckets and let the water sit overnight to get it to at least room temperature however this will still be a good 10-15* lower than tropical. Should I get an extra heater and just do 5G at a time water changes? Should I overheat a 5G bucket and then have a room temp bucket that will hopefully balance out?

What's the best way to put new water in that won't stress the fish during the winter months when my tap water is cold?
  • #2
Do you not mix cold and hot water from the tap together to get the right temp? Or do you allow the water to sit 24hrs to de-chlorinate and gas off?
  • #3
I always adjust the water between the hot and cold tap and guesstimate the temperature. I've never notice a temperature fluctuation yet that way.
  • Thread Starter
  • #4
I use Prime for de-chlorination. As far as using hot / cold mix for some reason I thought you don't want to use hot water in a fish tank (due to sediment and buildup that occurs in hot water heaters).

So, I guess I am being overly paranoid about water quality then?
  • #5
I wouldn't say over paranoid, but even if there was any sediment the Prime would probably help with that. I would be more worried about the temperature fluctuation then that.
  • #6
I use Prime for de-chlorination. As far as using hot / cold mix for some reason I thought you don't want to use hot water in a fish tank (due to sediment and buildup that occurs in hot water heaters)...
No worries at all. There is sediment in the heater but it remains stationary.

A basic cooking probe thermometer or a cheap infrared thermometer are good for getting your WC water the same temp as your tank water. I always try to get my WC water within a degree or two of the water that is already in the tank before it is added.

The probe is the cheapest and can risk getting wet.
  • #7
It is not necessary to use either of those. You can get it close enough by the feel of the water. As I said, I've never noticed a temperature fluctuation on either of the two thermometers I have in my tank using this method.
  • #8
Good morning,

Many members do use the touch method to test the temperature of the water, however, I'm with JRC3, I need to see #'s. The inexpensive aquarium thermometers below work great:

It's highly recommended that all new water going into the aquarium be the same temperature, within 1 or 2 degrees, as the water in the aquarium. Sudden temperature changes can lead to stress, ICH and issues you really do not want.

Folks that use a Python water changer or other similar device usually mix hot and cold water to get the desired temperature:

I use a 29 gallon aquarium to prefilter, heat and treat my water prior to it going into my display/show tanks:

Your thread has been moved from Cleaning and Maintenance to Aquarium Water/Temperature section of the forum. You can always locate your threads by clicking on My Threads in the blue bar close to the top of the screen.

  • #9
I take my thermometer out of my tank and use it to test water in bucket and add hot water before adding de-chlorinater.That way I can control temperature better, if that makes sense
  • Thread Starter
  • #10
thanks everyone...I have an IR people thermometer that I found works well for fish tank measurements so I'll probably use that to get me close.

I was always from the school of thought that hot water was used for cleaning...any time you need water for cooking purposes you should always use cold and then heat it externally, so I carried that train of thought over to fishcare.

Thanks again everyone.
  • #11
I use a 100 gallon prep water plastic barrel that I fill up and treat with Prime to remove any chlorine or chloramines. The barrel is also fitted with a sump pump with an add on sponge filter so that I can pre-filter and circulate the water from the bottom of the barrel to the top. It is set up so that it returns the water to the barrel above the water line so that it aerates the water which helps with oxygenation and gas removal. I have also placed a 400 watt heater in the barrel so that I can pre-heat my water to 80 degrees. I keep all my tanks around 78 to 82 degrees due the species I have so heating my water to 80 degrees keeps me within the 2 degree difference.

I know this is not a suitable solution for everyone but it works great for my 18 tanks. Before I got the barrel I use to fill up buckets with a hot/cold mix and used a floating thermometer to get the water as close to the tanks temp as I could. Because this was very time consuming I started using the 100 gallon barrel.

I have also purchased water hoses made for use on RVs to fill the barrel and drain the tanks. Be sure to not use plain old garden hoses for this because they are treated so that they don’t grow algae inside them, be sure to use one that is drinking water safe.
  • Thread Starter
  • #12
Bow - Once I am finally able to sell my house and move into one with a little more room that sounds like a great idea...currently though I am extremely limited on my options. I have no basement and no garage so storage space is at a premium.

One question you might be able to help me out with, right now I just use a smaller bucket to fill the aquarium after taking the water out...does anyone know of a relatively cheap water pump I can use to put the water back in? Lifting the bucket above my tank and using a siphon is not an option at this time.
iZaO Jnr
  • #13
I found a step ladder works fine to lift yourself abit. Since I got my bigger tanks , i've been using an "Atman" water pump and a 35 gallon barrel to change water (no idea what its model etc. Was second hand.), the gph is up to you, but just don't overdo it incase you need to quickly cut off flow.

Any water pump will work provided you can attach a siphon tube to it's outlet, from there you let electricity do the rest

I would recommend a lower-end gph if you're using a small bucket because you don't want your pump to run without water! That is unless you get a bigger bucket!

Good Luck

EDIT: Sorry, I forgot to mention the pump does pump at 300 odd gph, and it is intended for a 110 gallon
  • #14
You can pick up a small water pump used in ponds or sump systems rather cheap. The only draw back to picking up a small pump that don’t move but about 5 gallons a minute is they don’t lift water very well over 3 to 4 feet and it takes time to replace large amounts of water. I can use a small one on some of the tanks close to my barrel but for the ones in the other end of the house I have to use buckets because the small pump just will not push the water that far in a timely manner. I too use a step stool when filling my larger tanks with a bucket because my parents built me too short to the ground. (have to blame someone for being short).

Similar Aquarium Threads

Lacey D

Top Bottom