api kh/gh test kit

[mattyparsons]

i was in my semi-local fish store two days ago, looking for a test kit for my tank's kh. without too much detail, they had an api test kit that had reagents to test for kh, and gh.

however, the box stated that it was for freshwater.

i brought the box to the fella behind the counter and asked if they had one which would test for kh in a saltwater tank. he told me that the api freshwater kh/gh testkit would work fine for my reef.

can i trust the readings from this kit?

i have tested 3 times since, and have gotten steady readings of ~8 dKH each time.

thanks!

[bertoni]

The KH reading is fine to use. The GH reading will work, but it's fairly meaningless in a saltwater setup, and the GH is extremely high, as well.

I'd believe the 8 dKH.

[flinka]

<a href=showthread.php?s=&postid=11476076#post11476076 target=_blank>Originally posted</a> by bertoni
The KH reading is fine to use. The GH reading will work, but it's fairly meaningless in a saltwater setup, and the GH is extremely high, as well.

I'd believe the 8 dKH.

Bertoni,

Can one also believe the GH reading would be accurate? If yes, couldn't one use their calcium test in combination with the GH test to determine the magnesium level?

GH - calcium = magnesium?

Thanks,

Mitch

[bertoni]

You could try. Over the long term, that won't be economical, and I'm not sure how accurate the kit will be. But since you've got it, it could be tried.

[mattyparsons]

yeah, i tried the gh test.

the scale on the chart maxed out at like 12 drops or something. ...30 drops later i still hadn't seen a color change in the titration.

[bertoni]

It'll take an enormous number of drops. There's a lot of calcium and magnesium in seawater.

[Billybeau1]

Testing general hardness in seawater is almost impossible with the hobby grade test kits.

You would need to spend over 200 bucks to get a kit that will test gh in seawater. Hach makes one.

I agree the API kh kit is quite accurate for the price. And easy to use. :)