Water change recommendations

The best thing to do is to add the water conditoner(s) as you fill up your tank like you have stated. If you go to the freshwater diy fourms there is another topic on this. I have never hear about any problems when using tap water in the winter. But I bet someone else can answer to that question.

If it has been a long time since a water change, they say you should do small and frequent changes to get the tank water closer to the tap parameters before you do large changes.

Do you have KH and GH tests? If so test the tap water and the tank water and take a look at how far apart they are. GH is the one that can go really high is you've been topping off with tap water for evaporation with no real water changes.

Without any test data, I'd suggest starting with 10% water changes. Every day or every other day, depending on how big a hurrry you are in. After 5 water changes, then go up to 20% water changes. After another 5 water changes, bump up the volume again. At this point you could go to 30% or maybe more if you want.

You can look at it mathematically, sort of complicated to explain so I'll only go there if someone is interested. The bottom line is that the actual waste in the tank is the number of days between water changes divided by the water change amount in decimal. So the wastes in the tank can get really high is you do small water changes infrequently. Like, a 10% water change every two weeks means that you have 14 days divided by 0.10 or 140 days of waste in the tank. To do large water change could be dangerous, more due to the differences in GH than tank pollution, but it is just better to go slow.

Yes, you can use the Python, be sure to add declorinator to the tank as you start the new water in. If you use Prime, it says to treat the whole 50 gallon tank vloume, even if you only add 10 gallons of water. And be very careful about the temperature, some home water supplies are less steady in temp in winter.