Water Changing . Straight from the cold tap or warm it up

[Caper]

I have 2 vacuum hoses that attach to my taps for my 29 gallon tanks. I don't use all cold water, I try to take the edge off it by adding warm. I find I have to keep an eye on the thermometer as on occasion the temp was creeping up too high so had to adjust accordingly. My 10 gallon I just add a mixture of warm and cold, again just to take the edge of the cold.

I use decholinator since our water has chlorine it it (didn't forget about the chloramines Alan!). Plus there are copper pipes in my place. I emailed the company about the dechlorinator and they said it was for all that kind of "stuff".

Caper

[alanmin4304]

The bacteria that can be a problem in a hot water cylinder that is not hot enough is legionella which causes legionaires disease. It is generally inhaled in the shower and is a problem for humans not fish. Not using water from the hot water system is an urban myth and is as much of a problem as vampires.

[keriboi]

I did my first cold water change today

Starting temp was 27deg

Changed 20% of water and refilled with 50lt of cold tap water

Temp dropped down to 25deg so pretty happy with that.

Im using Seachem Prime to remove chlorinated water.

Is it better to add a small amount to each bucket I add or just add one amount when water change is done?

[whetu]

In winter I use warm tap water for changes, in summer I use cold. If I only had barbs in my tank I would use cold all year round, but I also have clown loaches which are more prone to white spot and like their water warmer, so the warm water changes are for their benefit really.

I add dechlorinator to each bucketful as I go - for me it's easy to add a drop while I wait for the bucket to fill, so that's how I do it.

Oh and I hang garlic above the tank to deter vampires.

[Ira]

If I used straight cold water over the winter my tanks would drop to about 16°/

[Shannon]

yeah I would not be doing water changes on my tropical fish with cold water. What a way to shock a system coz I can tell you right now if my core body temp dropped by something like 6-10c I would be dead.

Tropical fish need the warmth to survive and they are not like us that can make our own body warmth they rely on their surroundings and a drastic change like that is just insane for them especially captivity bred fish that havent grown up in the wild with flooding and monsoons etc.

[lmsmith]

water changes shouldn't drop your tell by 10c. If you were to do a as with cols water, you might drop the temp by 4c - 6c. Remember, the temp of the water out of your taps isn't freezing. On a usual day, the Water out of my taps is about 10c, and by the time you mix that with tank water, it's not really a problem. I'm sure it would be if you live somewhere cold though.

[alanmin4304]

Depends how much water you change.

[suphew]

Lets say you change 10% of your water, and the new water is 1/2 the temp of the tank, doesn't that equate to a 5% change in the water temp of the whole tank?? Or a temp drop of about 1.25 degrees? Then take into account the substrate glass etc that is holding heat and I think the change would be even less. For thousands of years fish have been living in ponds and streams that would have drastic temperature changes, rain, different thermal layers, cold steams entering warm ponds, day and night temperature changes, etc etc

[phoenix44]

does any one out there have a rudimentary Calorimeter?

I don't have access to the physics labs at Massey any more, but it is easy enough to know how much the water temp will change by if you know the volume of warm water (although it needs to be in grams because the unit of measurement is mass), the vol of cold water being added, and the temperatures of the warm and cold water.

the specific heat capacity of water © is 4.18 J/g^(–1) K^(–1)

[alanmin4304]

I change a lot more than 10%. 10% is about as useful as a proverbial. If you change 50% and cold is 10 deg and tank is 30 deg final temperature will be 20 deg will it not?

[Adrienne]

I change a lot more than 10%. 10% is about as useful as a proverbial. If you change 50% and cold is 10 deg and tank is 30 deg final temperature will be 20 deg will it not?

Absolutely correct!!!!

[lmsmith]

actually it doesn't work like that. The temp will be about 25deg. When you add cold water, the water in the tank raises the temp of the water and lower the temp of the tank water. It's all about equilibriums - you can't do 30 - 10 = new temp.

[phoenix44]

actually it doesn't work like that. The temp will be about 25deg. When you add cold water, the water in the tank raises the temp of the water and lower the temp of the tank water. It's all about equilibriums - you can't do 30 - 10 = new temp.

:bounce:

agreed! 100%

it took me ages getting my head around how temperatures work, darn all those chemistry and physics classes. I must have sounded like a total nerd with my blurb above

[gilly]

I change a lot more than 10%. 10% is about as useful as a proverbial.

I think it realy depends on how often you do the 10% changes

I am planning on setting up an auto water change system doing approx 10% a day on a timer and filtering through a carbon block removing chemicals. I thought this would be quite effective along with a couple of gravel vacs a week.

[Ira]

actually it doesn't work like that. The temp will be about 25deg. When you add cold water, the water in the tank raises the temp of the water and lower the temp of the tank water. It's all about equilibriums - you can't do 30 - 10 = new temp.

I have no idea what you're saying there.

AFAIK it does work that way, two equal masses of different temperatures, mix them together the end temperature will be the average of the two.

Yeah, your gravel, the tank itself etc will change the end results, but I think that would be drowned out(Pun intended :lol: ) by the couple hundred kilo masses of the water.

Which is why I say my temp would drop to 16ish when I do a 50% water change, over winter my water comes out of the tap...Not freezing, but close enough if you were to jump into my rainwater tank. I measured it once at 8°.

[phoenix44]

I have no idea what you're saying there.

AFAIK it does work that way, two equal masses of different temperatures, mix them together the end temperature will be the average of the two.

i understand the logic behind that reasoning.

In reality however it does not work that way!

it is quite hard for me to explain how it really works as well.

there is a formula to explain what is "happening" when you mix water from two sources at 2 diferent temperatures.

delta H = m.c(t-t1)

the most important thing to remember here is that cold water does NOT become hot. EVER. to do that you need a lot of energy. Tht's why you boil water on the stove or in the kettle.

Energy always flows from HOT to COLD. and although it would seem perfectly logical to assume that when combined- the two temperatures result in an intermediate (average) temp - it doesn't work that way because of the sort of reaction that is taking place.

the reaction is completely dependent on things like the surface area of the hot object (in this case water) \ and mainly the spec. heat capacity of water.

[phoenix44]

for more info try looking up Newtons laws of thermodynamics, and enthalpy and entropy changes.

hope this helps

Sorry about being so technical. Don't blame it on me. It's all Newton's and Einstein's fault :evil:

[sandysme]

does any one out there have a rudimentary Calorimeter?

I don't have access to the physics labs at Massey any more, but it is easy enough to know how much the water temp will change by if you know the volume of warm water (although it needs to be in grams because the unit of measurement is mass), the vol of cold water being added, and the temperatures of the warm and cold water.

the specific heat capacity of water © is 4.18 J/g^(–1) K^(–1)

[alanmin4304]

I don't have a calorimeter but I do have an easy connection to a hot tap.

[phoenix44]

@ alanmin

lol

that solves the problem aye! haha :lol:

the whole water temp thing has gone so far off topic!

[dcase]

I have one of the valve gadgets that fits on my tap .. the tap is a combined hot/cold (with a lever to move either side to change temp).

My wife controls the tap with a hand on the steel nozzle of the tap (that way she can feel the temp of the water flowing through). I have the other end of the hose and feel the water flowing into the tank (and also keep an eye on the temp gauge). Generally I never have to say the water's too hot or too cold as my wife manages it pretty well.

Also in Chch we are lucky with the water so don't have to leave it sitting.

I do 30% water changes every 2-3 weeks with no probs and the whole process is very quick as the valve sucks the water out while I gravel vac .. makes it all quite simple

[richms]

I put a hose on the bath spout and control it with the shower mixer when doing a consireable water change, for topups or small changes I just use the garden hose and do it in the evening when the water should be warmer (in theory, I have no idea if its true or not)

[Luke*]

heat your water! don't forget these are TROPICAL fish... so even the rain in their natural habitat is tropical! put your hand in a tub of 5 degree celsius water see how long you can keep it in there.. compare that to 27 degree water. most fish have some form of disease hiding away and unlike humans they are very delicate. even with humans.. add winter and how many people get sick? if you were frequently exposed to the cold your immune system would suffer too.

DavidR add a airstone too man that's what i did for my discus worked a treat i was changing 200L/day preheating and had an airstone cranking at the bottom... saved heaps of bucks on water ager.

[Luke*]

and is as much of a problem as vampires.

Underworld 3 comes out next year