How to convert my aquarium to softer water without killing my guppies

[Marylyn]

Hi all, I need help. I have several tanks but I am only having problems in my guppie tank. I had hard water and we went with a water softener.  I use the bypass when filling the tanks but the hot water is soft. I have lost 3 guppies this week. My ph is 7.8 right now. I use a python to do my water changes. Will I have to go back to using a bucket? I also put prime in when I change the water. Please help if you can. Thank you

Edited November 24, 2020 by Marylyn

[ange]

Try adding something like a wonder shell to increase the gH in that tank only. It releases minerals over time and needs to be replaced periodically but may solve your problem.