Ammonia In Tap Water

Such small amounts at room temp are fine. When I get to the end of refilling my tank the last bucket is usually less than a full one (ie less than 9.5 litres) so I use just cold tap water - and in winter that can be 6 or 7 deg C.

This is a little off topic, but it didn't seem to make sense to start a new thread.

There is a third type of domestic hot water system in addition to combi boiler and boilers that use a cold water header tank.

A year ago we replaced our combi boiler with what's called a system boiler. It stores hot water in a tank, but is a closed system so doesn't have cold water header tank. Because it is a closed system, I actually use hot water from the hot tap to fill my fishtank. (With cold water to try and match the tank temperature).

I'm curious what the experienced fishkeepers think of this?

Edit to add:
And water changes on my 240l tank take a couple hours. I have a 15l out bucket and a 10l in jerry can shape bucket. And my tank is not really near any windows or doors, so all water changes rewuire me to lug buckets across the house! Water changes on my new 25l hospital tank were a dream - it's about 1m from a sink and tap!

@Helen Im not quite as sure, the system boiler bit only describes how the central heating side of the boiler works, it could be used with a vented or unvented cylinder (with or without the tank in the loft) You say no tank so it's unvented but there are several types of these, some will have copper coils that the tap water flows through, others heat the the tanks with a coil that the central heating water flows through and the water in the tank is what you get from the taps. This second type will definitely be okay because the tank has to be stainless steel. The first type is probably okay but a quantity of tap water (5 litres perhaps) will sit in the coil for long periods at elevated temperature and could cause copper contamination. If you were to run off hot water for a couple of minutes after you feel it run hot I think this would remove the risk.

@Helen On the time to do a water change. I started with buckets but quickly got fed up with all the tramping around and risk of spillage so I now have two 'house hoses' and syphon water into a plastic dustbin that has a sump pump, the type for emptying pools or ponds, in it. I have two hoses because the of the length of the hose creates too much resistance to get a decent flow. When I was buying the hose I saw there are three sizes of hoze 12.5mm is the common one but you can also get a 15mm? and a 19mm. The garden centre didn't carry any hose fittings for the larger size so I went with standard hose and two lengths in parallel. I have since seen the fittings online, Gardena and Hoselock both have a professional range of quick connects for the larger sizes. Using this method I get a 160-180 litre actual change amount including packing everything away in under 45min. The hoses and pump cable coil up and live in the dustbin and is sooo much easier.

@Helen I would attach a picture but I'm sure it would fail and drive me nuts again. IM me if you would like one by direct email.
So correct, two hoses from the tank into the bin, I have a weighted screw top tub with dozens of 2mm holes drilled through the sides and two male hose quick connectors through the lid The syphon hoses (2off) attach and end in the bin. I have quick connects on the bin ends as well so I can pour (or leave) water in the bin and pump a small amount from the bin into the tank to start the syphon.
Once the syphon start, disconnect the hoses from the pump and connect two long hoses that go to a drain, sink or garden, these also have quick connects on both ends. The tank will drain down in 4-5 minutes, if I need to vac the substrate I also do this into the bin.
To refil I connect the long hoses to the syphon hoses with two straight quick connects and the other end of the long hose now goes to the taps or in my case a buffer store of aged, temperature controlled, dechlorinated water. You could of course fill the bin straight from taps blending to the correct temperature, dechorinate it a bin at a time and then pump it into the tank through the syphon hoses. Bins hold about 60 litres I think.
This will sound complicated I'm sure, a picture would have been better, but it is really is very efficient the with the only connectors in bin so any connector leaks don't matter