Water changes - drop in temp

**sarahp**

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So I didn't want to hijack the thread that Abbeysdad had started about volume and frequency but having read that thread, and the fact that the clocks have just altered in the UK for winter it got me thinking.

I always do 60%-70% water changes - my tank is approx 250 liters and I just syphon water out via a 25 meter pipe into the garden.

In the summer doing that alters the temp in the tank from it's normal stable 25 to about 20/21. So quite a drop but not too bad and only takes a few hours to come back up to normal.

However, in the winter it's much more of an issue. If I pull 60%+ out and refill via the cold water hosepipe it can drop the temp down to 18 or 19 - not ideal to say the least. As a result I have the dilema of less water changed or having pans of water heating on the stove and kettles boiling like mad in a bid to raise the temp of the water as I put it in.

I'm sure I read somewhere that water out of the hotwater tap is not good as it has too many metals in in??

So my question is this - what do the rest of you who live in the UK , or other places where jumpers are a necessity, do about stabilising the water temp during changes??
 
What kind of boiler/hot water system do you have?

If it is a combi boiler, you can use hot tap water.

If you have a hot water tank in the airing cupboard which is topped up from a cold tank in the attic, I would not use the hot tap.

The reason is not metals as your dechlorinator should take care of them. It is because the header tank in the attic is not sealed. All sorts of things have been found in there including dead rats and pigeons. We regularly get wasps nests in the attic and I can't stand wasps. So at the first sign I get someone in to get rid of them. This includes spraying wasp killer in the attic. I have found dead wasps in the header tank - were they contaminated? I don't want to risk anything getting in my tank so I boil a kettle to warm the water in the bucket I use to refill the tank.
 
I think you have a few options...

-> 60-70% weekly, according to most experts is a bit much, especially if you do other tank maintenance that keeps nitrates low(er) and/or you have a planted tank. You could cut back some to would lessen your temperature differential.

-> In the winter, you might do a 25%+/- water change twice a week.

-> Depending on the type of hot water heater you have, you could use some warm water to offset the cold. I don't know anything about hot water heaters in the UK (but would hope that you don't have dead things in there!) - here in the US they are pretty much all sealed and glass lined so there is no real concerns. Before realizing I had high nitrates in my well water, I got a hose adapter for the sink faucet. I found the right faucet settings for the correct mix of hot/cold water, and used a sharpie permanent pen to mark and index the faucet(s). Close to exact temp. every time.

-> you could take a much different approach. I have to pre-filter my water for water changes. I bought an inexpensive submersible pump (an ECO 396 about $20-25$ USD) and place it in an 18g sterlite bin filled with (in my case filtered) water. Then pump the water into the tank. You could boil a small pot on the stove and add to the bin filled with cold water to bring up to warmer temp.
 
I use a 20 gallon drum to pre heat and treat the water overnight before pumping it into my 6 foot tank
 
I use a 20 gallon drum to pre heat and treat the water overnight before pumping it into my 6 foot tank
There you go @saralp, get a spare heater and a bin and set it up the day before your WWC....(AND you'll have a spare heater should your tank heater fail!)
 
Thanks for the tips guys!

My hot water boiler is the combi sort that Essjay says is ok so I could get a tap connector and pipe it in via the kitchen tap.

Being a bit of a nerd (and having had a heater fail in the past) I do have a spare heater just in case so could try Nick's idea.

I shall experiment over the next few weeks and get back to you with results :)
 
i do 25% weekly and have never found any need to heat the water. though during winter i let it sit for an hour or so before i use it.
the activity, during the change, of my fish would seem to indicate they are less than stressed by the change. indeed if say they seen to revel in it. been doing this for 10 years now with no ill effects.
 
I must ask, where does your temp reading come from? Is it a stick on glass thermometer? If so it will not give you water temp it will give glass temp when water is drained. Just a thought.


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