# GH TESTER or TEST KIT



## jbyoung00008 (May 16, 2011)

Hey everyone. Im tired of trying to guess how many drops Ive used on my API GH tester. For some reason I have a hard time seeing it change color from green to 

orange. It may be out of date. Is anyone using another tester that works well or if you have any other methods Id like to hear them. 

Thanks


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## hp10BII (Apr 23, 2010)

I use API test kits but I rarely use their GH test kits. I use a tds meter that measures total dissolved solids in your water. Instant read without dealing with vials and reagent drops. In a new setup or just as a check from time to time, I would compare the GH test kit to readings on the meter. It is a comparative reading because a GH test kit measures calcium and magnesium, a tds meters measures that as well as any other compounds you might add ie. sodium chloride, calcium carbonate, sodium bicarbonate. So what I do is get a baseline reading from the GH test kit to what your water readings should be and compare it to the readings on the tds meter.

So for example, for me, a GH reading of 10* would be roughly the same as 200ppm or 370Ms on the tds meter. I think the ratio is something like 1* GH = 17.9ppm = 33 Ms


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## 2wheelsx2 (Apr 21, 2010)

A TDS meter uses conductivity to convert to a number interpreted as TDS so it would encompass everything dissolved in water including fish waste and uneaten food (ones which are soluble in water) so if you are after true hardness of the water it's best to use the pen in the water before you put it in the tank (if you're pre-mixing) or right after a big water change. Otherwise you would be measuring organics in the water too. It's not uncommon in my tanks for the TDS to rise by what's interpreted as 50 PPM in hardness over the course of a week before a water change if I'm feeding heavily.


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## jbyoung00008 (May 16, 2011)

Thanks you two. Very helpful information

I have a tds meter at home I will start using it. Is there any where on the internet that offers a chart to compare my results too????


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## hp10BII (Apr 23, 2010)

Not a complete chart:

Kent Marine Â» R/O | Products | Water Care


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## jbyoung00008 (May 16, 2011)

Looks.good to me. Very simple. Thanks. Ill post my readings


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## jbyoung00008 (May 16, 2011)

Im measuring my GH today before and after water change using a digital meter that reads PPM's

25g was at 360ppm
120g was at 400ppm Both seem a little high. I will see how they are after 50% water change

I also found this chart online
0 - 4 dGH 0 - 70 ppm very soft
4 - 8 dGH 70 - 140 ppm soft
8 - 12 dGH 140 - 210 ppm medium hard
12 - 18 dGH 210 - 320 ppm fairly hard
18 - 30 dGH 320 - 530 ppm hard
over 30 dGH over 530 ppm very hard


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## jbyoung00008 (May 16, 2011)

After a 50% water change both tanks dropped 150ppm


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## hp10BII (Apr 23, 2010)

Curious what your nitrate readings were, either before or after the water change?


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