DH and KH testing results

Ali

Ali

Active Member
I picked up an API test kit for hardness. For my 37 community tank I got a dKH of 2 and a GH reading of 125.3

Haven't found a good chart online anywhere to tell me where these fall in the spectrum. I was surprised to see the KH so low (though I have no reference for what is "low" or not), as I add calcium carbonate with every water change.


Sure there's a great reference chart online somewhere, but so far Lord Google hasn't delivered it yet.
 
pbmax

pbmax

Active Member
A dKH of 2 isn't unusual in our area, but it is low. Carbonate hardness is most easily increased by adding baking soda. I use a product called Seachem Alkaline Buffer to increase the KH in my tanks when necessary (I was at dKH 7, dGH 8 on City of Lacey water as of last weekend, no tweaking necessary). I like to maintain as close to 8 dGH and 8dKH as I can to keep my platies happy. My other aquaria don't mind the higher GH (dwarf shrimp, kribs, corys), which is good. :)

Your GH value is in ppm, which is 7 dGH - this is decent - great for neocaridina and most snails.

Lower GH and KH are desirable for softer water fish. Higher KH gives you more PH stability and higher GH is necessary for certain invertebrates and fish that prefer harder water (livebearers, etc.). Certain plants also require higher GH and most plants will tolerate higher GH than they prefer. High-GH plants will die in a low-GH environment.

To answer your question: it all depends on what sorts of fish you're raising. For a general purpose aquarium I'd shoot for a dKH of 4 or 5 - this will give you buffering capacity to resist PH crashes. You can google baking soda dosing information, or buy a product (usually not too expensive). GH is a bit trickier... yours is fine for most fish, though for softer water fish you'll need something like a RO filter to reduce it.

I've been modifying GH and KH in my tanks for years with a little digital scale, some math, and seachem products. It can be a pain, but it's made a world of difference for my platies.
 
GinnyFinny

GinnyFinny

New Member
Hi Ali:

The API KH/GH kit has a pamphlet that one tiny section is in English - on the back page - it's called GH & KH CONVERSION CHART. So you can either read your results in ppm or °dKH. My GH stays at about 170 (9 drops or 9°) but and my KH runs at 20 to 30 ppm or 2°dGH. I live in Edmonds and the water is a little harder here than other towns. I sort of wish my GH were 125. Cory at Aquarium Co-Op said 170 and even up to 200 ppm is nothing to freak out about. If you really want PURE water, you can buy DI water at the Water Store on 10th NE and 179th St. in North Seattle (206-363-0039). You need to supply your own bottles and then buy Seachem Equilibrium to replenish the necessary elements the the de-ionization process strips the water of. Okay if you don't have lots of tanks or BIG tanks.

HEY, BY THE WAY, I HOPE YOU'RE STILL GAME FOR TAKING CARE (fish-sitting) OF MY AQUARIUM starting around May 10th. I should be moved out of Edmonds by the 13th and then I have to take off for California on June 17th for 3 weeks. I'll call you and make sure you're still on for this job - the fish kennel Queen!

p.s. the D.I. water is 40 cents a gallon. I have 3 5-gallon bottles, so that's 3 water changes for me (25%) weekly.

Ginny Williams
 
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