Aging water

[cow]

Hello, I need to ask someone if it is okay to let water sit in gallon jugs for 5days before doing water change, I am getting water from my local fish store (way different then mine at home with the tanks) to get them used to the fish store water so they can move there, they are old and need better tanks and water, I worry about this decision but was assured by lady at pet store whom i know, and it is a privately owned place, that she will take good care of them, but in the meantime i have been getting water from them to get my fish used to it, i have to do a water change and it has been sitting in gallon jugs for 5 days tomorrow, is this safe for them or can water get old and nasty?? Also wanted to know if changing out a gallon each day in this twenty gallon tank is okay as i wanted to change it slowly, will this be okay to keep the water safe for them, SInce Monday 4 days ago, i have changed out 2 gallons on Monday and a gallon each day since, this is now Thursday night, will do more tomorrow , or tonight if you think i should and the water is still okay after sitting for 4-5 days with no lids
Thanks

 

[HUKIT]

This seems like alot of work, why not just bring them to the LFS and let them drip acclimate the fish for a couple of hours? This will slowly acclimate them as needed, more often than not your local fish stores water will be somewhat similar to your in terms of PH.

 

[Cactuspixie]

Hello, I need to ask someone if it is okay to let water sit in gallon jugs for 5days before doing water change, I am getting water from my local fish store (way different then mine at home with the tanks) to get them used to the fish store water so they can move there, they are old and need better tanks and water, I worry about this decision but was assured by lady at pet store whom i know, and it is a privately owned place, that she will take good care of them, but in the meantime i have been getting water from them to get my fish used to it, i have to do a water change and it has been sitting in gallon jugs for 5 days tomorrow, is this safe for them or can water get old and nasty?? Also wanted to know if changing out a gallon each day in this twenty gallon tank is okay as i wanted to change it slowly, will this be okay to keep the water safe for them, SInce Monday 4 days ago, i have changed out 2 gallons on Monday and a gallon each day since, this is now Thursday night, will do more tomorrow , or tonight if you think i should and the water is still okay after sitting for 4-5 days with no lids
Thanks

Is this water from their aquariums or just from their tap? If its the first, and has been sitting still for 5 days I wouldn't use it. If its the second, then it might be alright. It wouldn't be alright in my house- the cats and dog would be sneaking drinks from it!
What are the parameters of your water compared to the water you are getting from the LFS?