water change help

[abomb]

The wate ri use for water changes i keep in jugs and have them sit afte ri condition them usualy at the very least a few days. I was curious however when i add the water it is room temp how stupid am i beng and wont this cause myu fish shock? or is adding the water room temp alright?

Adam

[BrianNY]

There are a lot of variables at work here Adam. Why are you holding water at all. What is the PH of your tank? What is the PH right out of your tap? The likelihood is that any chlorine remover would make it practical to do water changes quickly.

Oh, and what fish are you keeping?

[mgkaelen]

adam, it's not necessary that the dechlorinate soaks into the water like you're doing. i'm not sure if this is the reason why you're keeping the water, but it's unecessary..

[Endgame319]

I only let the dechlorinated water sit for an hour or two before I add it too the tank, I dont see why you would wait a few days. And as long as your only adding a small amount (10-20%), it shouldn't have too much of an effect on the temperature of the tank to cause any damage.

[lyquidphyre]

I just finished doing a water change =o)

If you are getting water from ur tap you can use dechlorinator and put it in the water.

I always fill up a jug, put in recommended amount of dechlor and when I am finished filling up my tank, I add in my pH stuff (recommended amount).

If you want to keep a ready-to-go jug somewhere to top off ur tank when the water evaporates you can do that. But I don't think its necessary to let it sit for that long =o)

[lyquidphyre]

Oh, also about the temperature- You can get a general idea of the temp of ur water and Just adjust the temp of ur tap to about the same as ur tank and you should be okay. That way it won't be way too cold or anything

[Kwenbee]

I was doing the same thing before I found this site. I read it SOMEWHERE in the massive reading I did online that you should let the water sit for 24-48 hours before adding it to the tank. Of course, that was when I was stupid enough to think I had chlorine in my well water (DUH).

That's probably what adam read as well. I believe it also said it in my tank set up stuff when I got my tanks.

[patryuji]

Slowly add the water over a long period of time. Water has a specific heat capacity of 4.18j/g-c. Therefore if the tank is a 30 gallon tank and you are doing a 50% water change there will be close to 15gallons of water in the tank (not counting the volume displaced by gravel and decorations. 15 gallons gives 57 liters and thus 238.26 kJ of energy for every degree celsius. If you have the tank at 80 degrees F (26.7 degrees c) your total energy is 6361.5 kJoules. Then you take the room temp water (we'll just arbitrarily say it is 70 degrees F or 21.1 C) and you can figure out how much water to add to keep from drastically changing the temps. Then add 1 liter of that water and you get 58 liters of water at 6431.5kJoules, divide by 58kgm, divide by 4.18 and you get 26.53 C (79.75 F). Now it may seem as if some of the stuff was unnecessary as it cancelled out in the end but there are some more factors to consider...1 watt = 1 joule/sec. If you have a 200Watt heater you can put 200 joules of energy back into the water every second...so you find that 58 liters of 80 F (26.7C) water should have an energy content of 6465.1kJ a difference of 33.6kJ from what we have...divide that by 200(watts from the heater) and you find that if you drip one liter of water into the tank every 2 minutes and 48 seconds there will be no change in temperature!

But wait, there's more! We have not considered the radiant heat given off by the tank, conduction of heat through the glass from the water to the air on the outside and thermal conductivity of the tank (whether it is glass or acrylic makes a difference) and then finally the convection of the heat amongst the water itself...so to keep this from being too difficult I say just use 75% of your heater's output (150 watts in this case) and you find that you should have 1 liter of 70 degree F water drip into an 80 degree F tank over 3 minutes and 44 seconds to keep the temps stable.

Maybe I should just make a little javascript so you can plug in your own temps and the like and it will tell you exactly what timeline should be used while hiding all the math from you? I could even have the aquarium dimensions as a field to determine the effects of heat loss to the room (or better yet, common sizes in a drop down list).

[patryuji]

I just realized an error...

as the volume of higher energy water increases the amount or speed with which additional water can be added will also increase. But to be safe just use the worst case scenario (initial water added) and there won't be anything to worry about.

[Fruitbat]

Excellent explanation, patryuji! Good lesson in thermodynamics.

abomb....lots of excellent advise here but here's how I do it: I hook my Python up to the faucet and drain out about 25% of the water in my tank (vacuuming the gravel while I remove the water). Then I adjust the temperature of the water coming out of my faucet to approximately the same as the temperature in my tank (I do this the scientific way....by sticking my finger in the water and adjusting the temperature until it is close to my aquarium water.). Then I reverse the flow of my Python and fill my tank right back up with fresh water from the faucet. Dribble in a little dechlorinator afterward and...voila!! 25% water change....no mess...no buckets....no jugs of water taking up space.

[Aquarian]

I do the exact same thing as Fruitbat... just a few drops here or there to wipe up afterwards. Dechlorinators are INSTANT so there is no need to have buckets sitting around. Try it, you'll like it!

also, I read that when doing the partial water change... it's ok to add slightly warmer water than what's in the tank than it is to add slightly colder water. Just thought I'd mention it since it's etched in my mind every time I change some water!

[Menagerie]

[center:87378d906c]8O [/center:87378d906c]
[center:87378d906c]I need a nap![/center:87378d906c]


BTW Aquarian--Lovely tank!

[Aquarian]

Oh thank you Menagerie!