[Mxx]

*That should of course read 'buffered' in the title!

I am seeing two widely different views on how ph acts in aquariums.

One view that the Ph in any aquarium will tend to drop over time through the production of organic acids from life, unless you buffer for that through water changes, adding nutrients such as calcium, carbonate, and magnesium to counteract that, or have crushed coral, dolomite, aragonite, or gravel/rocks which contain something such as lime which will dissolve over time.

And the other view which I found in Walstad's book is than an NPT will naturally buffer ph at around neutral without any of that being necessary, but I didn't think it described how or why. So my question is, how and why would it do that?

If the former case is true does that for instance cause our oceans to indefinitely grow saltier over time?

 

[OverStocked]

Doing water changes will prevent the extended build up. As a whole, we want a lower pH/lower kh in planted aquariums than some would in other freshwater tanks. There is almost never a reason to use buffers in a planted tank if you are using tap water.

 

[lauraleellbp]

If you're talking about a Walstad setup, she adds calcium carbonate into the substrate.

The oceans stay at a set salinity due to the constant re-introduction of the water that evaporates off (rivers, rain, melting icebergs, etc). Plus don't forget that 70% of the earth's surface is water and the vast majority of that is oceanic- that's a LOT of water volume!!! lol

Regular water changes maintains stability in my own planted tanks.

 

[Mxx]

Calcium carbonate in the substrate, well that's certainly good to know as I missed seeing that if it happened to be in her book! If so then that slightly undermines the book's statements that NPT's naturally balance their own pH though, even despite a lack of regular water changes in Walstad's tanks.

Using a bit of calcium carbonate for buffering was something which I'd been planning on doing anyway, but using a bag in the filter instead which I expect would be equally effective, and so that I can better control its impact upon hardness by adding or reducing it as necessary if I'm trying to run a relatively soft water tank. And I'd heard that 2 tablespoons of crushed coral was sufficient to buffer a 55 gallon tank, although the recommendation didn't state what the resulting level of hardness which that was sufficient for maintaining.

 

[lauraleellbp]

It's been a few years since I read her book, but I believe she adds dolomite or something high in calcium carbonate...? I remember a bit about how Vals were one of the plants studied as able to absorb it through their roots for their carbon needs...