when i do a water change i take out 50% of my water which is about 70 gallons give or take!!! 135 gallon tank
i have no way of adding water 70 gallons worth that is at 80 degrees like the tank
so when i add the 70 gallons back in i just use the hose from outside and it brings my temp down to about 70 degrees in the winter time and in summer time like now it only brings tank water temp down to 77 degrees which isnt much

i no people say dont do that but i havnt run into any problems yet after all these years of doing it.
am i the only one to do this?

no... i normally do that too... but was told in the other thread...
it will depends on your tap water condition. if you have high chlorine
concentration, you need to treat it first to minimized possible shock
for the fishes.
see this thread : oscarfishlover.com/oscar-fish-advice-for...water-changes#100951

oh yes of course i always add prime before adding the 70 gallons back in!!!

I do that for 125 and both of my 55's. My O's love swimming against the heavy current.

I bring my hose in the house and add it straight in the tank. 50% or so water change. It comes in at about 72 degrees bringing my tank to around 73-74degrees. Within several hours its back up to 78degrees. I think the fish enjoy the cool water baths.

Wish I could do that but I have to add in hot water as my well water is very cold (about 60F). I tried it once and it was too much of a difference for the fish. Now I try to match temperature (within reason) to prevent a shock to their systems. For other fish and tanks, I try to simulate rainy season by dropping tank temp and frequent water changes to promote breeding.

you want an easiest way to do water temp balancing.... put the water in a huge kettle
or cauldron over a your stove.... with fire going on, put you powerhead running
transferring the water..... there would be not much difference in temp when done

if you get a huge bin or container , like the ones you use to collect rainwater in your garden, you can fill that up before hand , prime the water and get the water at room temp.( or heat it for some time)
I use that technique for salt water changes in my puffer tank, and i use a small pump and a heater to get the temp close to the actual temp in the tank.
Too large differences in temp will increase the fishes susceptibility for some diseases, so it's best to keep the temp during waterchanges steady, if possible.

I generally as a rule try not to change any more than a third of the water at a time. I have always refilled the tank from the hose and have never noticed any huge spikes either way (hot or cold) to the difference in the tank. If the gph of your filter is high enough, the tank should be fairly even really quickly. I am filtering roughly 550 gph with my 2 canister filters in a 125 gallon tank. I have never noticed any adverse affects to the water temp of the fish. I also do like cebo does and do not keep any of the hose outside that doesn't have to be. Just my thoughts.

generaly the bigger the tank the less the problems because theres more space to comtaminate i run a fifty gallon bowfront tank with a fluval 305 so with these two factors water changes arent as important i still do my changes but only every three months or so and my water quality is perfect and same with ph nitrate nitrites and all that other crap and as for heating i run two heaters in my tank each good for a sixty gallon tank (i no its over kill) so in the case my tanks too cold it heats up fastttt

I'm running a 125 Gallon and I do the same thing. I do about a 35-40% water change every other week (work constraints, otherwise I would do it weekly). I fill it back up straight from the hose, treat it immediately after with some NovaQua and StressZyme, and my Oscars nor water quality has ever had any trouble.

I'm running 2 heaters, though, so that probably gets the temperature back up.

I'm also filtering through about 1,240 Gallons an hour with my filters.

I'm running an AquaClear 110 (500 GPh), an Emperor 400 (400 GPh), and two AquaTech Powerheads (170 GPh) each.

Water quality has never been an issue for me in any of my freshwater tanks. As long as you have good filtration, you're treating your water when you do changes, and you're changing it at minimum once a month, you should be fine.

I got a 110 US gallon tank that i do 50% water changes (I got 2 aqua clear 70's which run 400GPH each...i know i need more, want to get a canister filter when i get some extra funds).

I use a similar device for water changes:

www.marinedepot.com/Python_25_Ft_No_Spil...TGSMS-PY1211-vi.html