Apologies, yet another newbie!!

[TwoTankAmin]

pH is a bit of a strange thing. Sometimes it matter and sometimes it doesn't. For the most part once can assume the harder that water is, the higher the pH tends to be and vice versa. But there are exceptions.

KH is what keeps pH high. One can not lower pH without dealing with KH. Thins of is as a sponge which absorbs acid. When the sponge is full, the pH can drop drastically. We normally do not worry about pH except for two things. The first is when we change water parameters. Even if this is not done for a pH reason, the pH will likely be changed. The second is why we do water changes. KH gets used up over time. For one, the nitrifying bacteria use is as an inorganic carbon source. Regular water changes usually replace it. So we really do not think about KH until there as a reason to check it. Fish themselves have no KH requirement.

I have one tank I run at a pH of 6.0 and TDS in the 60 ppm range. WHen it was first stocked it was 4.2 and 30 ppm. For that tank KH matters and I use RO/DI water even though mine is neutral and softish to start.

 

[Ch4rlie]

Interesting.

I guess it entirely depends on the species of livestock you wish to keep, particularly wild caught where the pH can be far lower that your water supply, so using RO/DI makes sense in this instance.

But if buying livestock from a local breeder / LFS then the pH should be roughly the same as in your home, so in this instance the general hardness may matter more as LFS tends to soften their water with their water system for all the types of livestock they tend to stock, so using tap water may be too hard so a mix of tap and RO would be the ideal perhaps until said fish you purchased and in your tank has '"adapted" to your water source over a number of week/months depending on the livestock specie presumably.

Just a hypothesis from top of my head is all.

 

[Ch4rlie]

Again, sorry if I missed it, but do you intend to keep fish, plants, etc that require a specific pH? Reason I ask and I'm sure you know this, but fish you buy locally are already going to be adapted to the pH that comes out of your tap. If you keep up on regular water changes, your pH should always match what's coming out of the tap. In my opinion, the last thing I'd want to do is target a pH different from my source water if I didn't have to.

No need for apologies, I did mention I would like to have some coryadoras, in particular Habrosus as wanted some of those for a long time and have had hard water and cories being soft water specie made it unlikely they would thrive in my tap water if left as is.

Hence my questions on RO/DI systems etc.

Sometimes LFS softens their water to suit their livestock that they currently stock, LFS tend to have a fairly complex water system that feeds on their tanks from one or two large filter so hence my assumption they must soften the water for the mixed variety of livestock species. I may be wrong in this tbh.

That being said, I'm a complete amateur compared to TTA, fishorama and noodle cats, therefore I would go with what they suggest given they've been at this longer than I.

I too am a complete amateur, in fact more like a newbie especially compared to TTA!! ?