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Discussion Starter · #22 ·
Ok, things make a little more sense now. After letting my water sit out for approx 24 hrs, the ph tests at 8.1. Gh is still 1-2 and Kh 12. I was wondering why my tank was always reading 8.1 when my tap (sans the 24hr wait) was at 7.4. Now I know my tank and tap are the same. Now to do some reading on RO to lower the kh and ph and maybe boost the gh.
 

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ah ha! LOL 8.1 makes more sense with that high KH value :smile:
 

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If you want to keep soft water fish then yes, I would blend RO with the tap water to get the KH lower, so you can get the pH lower.
The most important value is the GH, and that is fine. But the pH is a bit extreme for most of the soft water fish.

You can practice with a gallon of RO from the grocery store.
Test a few blends like
25% RO + 75% tap
50/50
25% tap + 75% RO
(Use aged tap water, or let the mixes sit out 24-48 hours)
Select whichever is close enough to what you want for KH and pH, then add some minerals to it to bring the GH up to about 2-3 degrees. Use a blended product that has both calcium and magnesium.

When you have figured out a recipe make the change slowly in any tanks that have fish. It might take a month to alter the water that much. That is safest for the fish.

When you buy fish, test the water they come in. Set up a quarantine tank that matches that water. While the fish are in quarantine do small, frequent water changes so when you see they are healthy (about a month) then they are also acclimated to the main tank parameters.

When you do water changes you will need to set up the water a day or so ahead of time.
 

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Discussion Starter · #25 ·
The fish I have now are fine with the parameters. I guess my biggest concern is whether or not a wide range of plants would grow and live in these params or if I would severely limited in my choice. By adding natural driftwood and using a co2 reactor, I would assume that my ph will drop. Hopefully my gh and kh will be okay for both the fish and plants.
 

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Can my my kh be high as in 214ppm and my gh be low? Or is my testing kit bad? I ask this because when I tested my tap water, my kh took 12 drops to change color and my gh had the green color on the first drop. I thought I read that this isn't possible. I am on well water south of Washington dc in southern Maryland. My tap ph is 7.4 but the tank water is 8. Thanks
KH and GH are independent of each other.

KH is a measure of the concentration of carbonates (HCO3- and CO3--) not actual Alkalinity (total capacity to resist acidification/pH drop). Because they're typically in significantly higher concentrations than other buffering agents in the aquarium, the terms KH and Alkalinity have been used interchangeably but they aren't the same, strictly speaking.

GH is a measure of the concentration of divalent (2+ charge) cations, typically calcium (Ca2+) and magnesium (Mg2+). Like KH, all divalent cations increase GH, but since Ca and Mg are usually so overwhelmingly present, they're usually the ones tested for. If you look at your city's water quality report you'll see General Hardness reported in ppm CaCO3 equivalents which is what your test is probably reporting to you.

It's entirely possible to have a very high GH with a very low KH if you're adding a lot of Ca and Mg relative to the carbonates in your water.

It's also quite possible for your KH to be high and the GH to be low if you're using tap water. As weather changes (lots of rain) or temperature increases, water treatment utilities often change how they disinfect the water, leading them to increase Alkalinity to prevent corrosion of the pipes.

It's also possible for pH to be high even though KH is low if the tank isn't getting CO2 input. Many aquarium plants will break down bicarbonate to get at the CO2 it contains, leaving OH- behind, which is a strong buffer, leading to an increase in pH over time.
 
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