chipster55

Can anyone tell me how to convert the GH and KH readings to dgh readings..I bought a test kit abd it shows my KH as 143 and my gh at 210...I am trying to figure out the dgh readings from those. I want to lower the gh for breeding..Any help would be greatly appreciated.

Butterfly

KH is carbonate hardness (measurement of carbonate and bicarbonate ions dissolved in water)
GH is General Hardness (measures calcium and magnesium ion concentration dissolved in water)
Aquarium Pharmaceuticals explains it this way

The General Hardness(GH) value is determined by the number of drops of the reagent that must be added to turn the water in the test tube green. Each drop is equal to 1 °dGH or 17.9 ppm GH
To convert °dGH to parts per million (ppm), multiply °dGH x 17.9.

The Carbonate Hardness(KH) value is determined by the number of drops of the reagent that must be added to turn the water in the test tube bright yellow. Each drop is equal to 1 °dKH or 17.9 ppm KH,
GH & KH RANGE - Aquarium Life
0°-3° (0-50 ppm) discus, arowanas, elephantnose, neons, cardinals, live plants

3°-6° (50-100 ppm) Most tropical fish including angelfish, cichlids, tetras, botia, live plants

6°-11° (100-200 ppm) Most tropical fish including swordtails, guppies, mollies, goldfish

11°-22° (200-400 ppm) Rift lake cichlids, goldfish, brackish water fish


Hope that helps
Carol

chipster55

Thanks so much...Exactly what I needed

chipster55

One more question...To lower the GH/Kh range can I just add plain R/O water (as opposed to adding minerals) during water changes?

Butterfly

To lower GH you have to remove calcium and Magnesium from your water.
Reducing General Hardness
General Hardness can be lowered with Aquarium Pharmaceuticals Water Softener Pillow. The ion exchange resin in the Water Softener Pillow lowers GH by removing calcium and magnesium ions. The Water Softener Pillow will not lower KH. Partial water changes with deionized water will gradually reduce GH to the desired level.
Lowering Carbonate Hardness
Lowering KH can be done by using rain water or Reverse Osmosis when doing water changes.
Carol

chipster55

Does the R/O not remove calcium and magnesium ions..Sorry for all the questions. I appreciate your answers.

pepetj

Adding RO processed water will lower both GH and KH, as a rule of thumb. Some other issues enter the equation: e.g. substrate (like crushed corals or marine sand will likely raise GH/KH); or driftwood (will likely leach tannins that will reduce your KH).

Since your GH = 210ppm = 12 dGH; and your KH = 143ppm = 8 dKH, you can safely try to tamper with these in order to drop or raise pH.

If during intentional softening of your water your GH drops dramatically, add trace minerals; keep an eye on the KH so it doesn't drop below 2.5 dKH or 45ppm.

Filtering through peat is a tried-and-true safe method of achieving this. Use Activated Charcoal media if you don't want your water to look tainted. Tea-colored water looks awesome to me, and some fish love it, but some people don't like it.

Do this gradually, it's better to err on the low side (e.g. adding peat and seeing no changes, than adding too much at once and experience a sudden change in pH) just take your time, and this will go well. After four weeks or so, the peat media will become inactive, and this will show in gradual, slow elevations of pH; just replace it and keep monitoring your parameters.

Pepe
Santo Domingo

chipster55

Thanks for all the info...I am getting a tank ready possibly for Discus so right now its empty (no fish) I am also going to live plants which is also a learning experience. I don't plan on adding any fish until I got a handle on this, thus all the questions..What, in your opinion, are ideal water conditions for gh/Kh readings. Also the ph from my R/O water is around 7 (light blue test color). Is that normal?

Butterfly

Yes R/O removes Calcium and Magnesium.
Carol