Increasing KH

Question
Hi Nicole,

I am hoping that you're able to help me with my question. I have a 20 gallon tank with one angel fish, two swordtails and two neon tetras. When I measure the PH it is consistent at around 6.8/7.0 but my KH is only at 3 dKH (according to my Sera KH test kit).

I just put in a couple of new plants and I understand that having the correct KH (about 5 dKH) is necessary for good plant growth so I'm wondering if you know of a way to increase the KH without increasing the PH?

Thank you very much for you time,
Loree

Answer
Hi Loree,

Raising the KH (carbonate hardness) is probably going to raise the pH a tad too, but that's nothing to worry about. Most angelfish (except wild caught species like Altum angels) do just fine in, for example, hard Florida well water like I have (many commercial angelfish are bred in Florida fish farms). Your swordtails will definitely appreciate harder water than you have now. The neons will probably be fine with the adjustment in water chemistry also, however, I am a little concerned you have neons! Did you know that these are what angelfish eat naturally in the wild? The rule with angelfish is, anything that fits in their mouth, will eventually end up going in their mouth...so might consider that as it gets to its mature size.

There are two ways to accomplish what you are looking for. You can either get prepared carbonate salt mixes, or you can make your own. The pre-prepped stuff is convenient, but for what's in it, much more expensive. You can make your own for far, far less money. The choice is up to you! Here's an example of a prepared mix:
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=4198

Here's an example of a do it yourself recipe:
Per 5 gallons/20 litres
1 teaspoon baking soda (sodium bicarbonate)
1 tablespoon Epsom salt (magnesium sulfate)
1 teaspoon marine salt mix (sodium chloride + trace elements)

Marine salt mix works better than "sea salt" from the grocery store, but you can make an experimental batch using this, if you would like. Here's an article about salts that really opened my eyes:
http://www.cichlid-forum.com/articles/aquarium_salts.php

What I would do, is execute a 1 gallon water change. Mix up one dose - enough to treat 5 gallons - and mix it with the new gallon of water you are going to put back into your aquarium (don't forget the dechlorinator)...then measure and see what happens. If it hasn't raised the levels sufficiently, repeat the process tomorrow. The trivial amount of sodium chloride in this mix will not hurt your plants, incidentally...I doubt it would even be measurable.

If the DIY recipe works for you, you can premix a bunch, store it in an airtight container, and you'll be all set!

I hope that helps, take care.
Nicole