I have very soft water. Should I adjust my ph?

Unfortunately I've come to realize I have crazy soft water, with very low GH and KH. I have 3 tanks, with a Molly in a hospital tank (so 4 atm).

My Betta tank is having ph swings from 7.4-6 (or possibly lower, no way for me to tell but I wouldn't doubt it).KH is 2.

I bought seachem alkaline buffer and acid buffer. I only just started to understand how KH and ph effect each other, so I don't want to make mistakes messing with the wrong thing. The only reason I'm considering it, is because I can tell the swings are causing problems.

My betta seems to have his finrot attempt to come back in tandem with the swings

My axolotl need a higher ph and hard water, and ph keeps swinging back down (I added a wonder shell which helped GH and kh, but KH went back down a bit)

My community tank ph is less important but I would prefer the water is at least a little hard because my snails in the past have had issues with growing their shells and my Molly couldn't shake his fungus in the tank (I'm making assumptions but I assumed it was because they like alkaline hard water as well). The ph seems to swing, but not as much.

Basically, for the most part I'm less concerned with the ph and more with the KH to keep things stable. Are these the right products for that? And what kind of dosing schedule would I need to upkeep?

 

One thing you could do to stabilize your tank is to add crushed coral. You can get it at any local fish store and it is not too pricey. Crushed coral will dissolve slowly in water that is soft and acidic (and stop dissolving once the water has reached a certain level), bringing up your hardness gently, smoothly and above all, consistently. Much better than adding chemicals that can bring in even more sudden shifts and disappear with every water change.
The coral will also add calcium and mineral content, making your snails happy. Once you have raised your KH, the pH will not be able to swing so much.

You can put the crushed coral in a mesh bag at the back of the tank - or in your filter if it fits. If you put it in the filter, it will work a little more quickly.

I don't know that it will clear up all your disease issues, but your molly will certainly be happier. Getting rid of the violent swings in pH will help your fish a lot.

 

One thing you could do to stabilize your tank is to add crushed coral. You can get it at any local fish store and it is not too pricey. Crushed coral will dissolve slowly in water that is soft and acidic (and stop dissolving once the water has reached a certain level), bringing up your hardness gently, smoothly and above all, consistently. Much better than adding chemicals that can bring in even more sudden shifts and disappear with every water change.
The coral will also add calcium and mineral content, making your snails happy. Once you have raised your KH, the pH will not be able to swing so much.

You can put the crushed coral in a mesh bag at the back of the tank - or in your filter if it fits. If you put it in the filter, it will work a little more quickly.

I don't know that it will clear up all your disease issues, but your molly will certainly be happier. Getting rid of the violent swings in pH will help your fish a lot.

To be clear, this will raise the KH as well? How long will it take, with how much coral and at what rate? And will it be okay with my betta as well?

 

To be clear, this will raise the KH as well? How long will it take, with how much coral and at what rate? And will it be okay with my betta as well?

Yes, this will raise the KH and the GH. It will also boost your pH.
I have it in my planted betta tank right now.

The amount depends on how much water you are treating. I have heard one pound per ten gallons.

Also, keep in mind that crushed coral is a slow process. If you do 50% water changes every week, you may wipe out some of your progress. If you prepare your water change water ahead of time, it is a good idea to add crushed coral to that too.

 

I was have a similar issue with the ph and I added about 1/4 crushed coral to a media bag in the filter. I have a 20g. For me, the ph indeed increase from 6 to 6.8 but it did take some time to work- several days to over a week so you’ll have to be patient with that route.