Best salt for fish-only + pH/KH contol

[GiannisK]

Hey all, new saltwater fish keeper here. I'm wondering what you guys think is the best salt? I've heard about some of them coming with phosphates or taking way too long to mix. I'm planning a 20 gallon fish-only tank.

I'm also still a bit confused about KH and pH.

What is the KH level I should be striving for? It seems there are different answers online. Or does it depend on the fish? How can I increase or decrease KH?

My understanding is that KH and pH will be significantly affected by the sand, right? In that case, how can you properly test and adjust the water before it's added to the tank and interacts with the sand?

I've also heard that my pH levels might be too low because of a lot of CO2 in my air (small space, few windows, lots of people). Is there a relatively inexpensive way to reduce CO2 levels? I don't have a protein skimmer. Is there media for other filters that can achieve this?

Thank you!

 

[Spare time]

The alk and pH level doesn't really matter much for the fish like it does for stony corals. I wouldn't worry about that. My favorite salts are by red sea and either of theirs will work for fish only. The red sea salt mixes in minutes compared to something like instant ocean. Instant ocean is the standard cheap salt but takes longer to mix.


The main concerns for fish keeping are disease, and its best to buy fish already quarantined or do it yourself and QT inverts in their own tank. The other concerns for fish are aggression and waste management.