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KH & GH testing

Discussion in 'Cycle your Tank' started by BMBLSAD, May 17, 2019.

  1. BMBLSAD

    BMBLSAD New Member

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    Hi all
    I am 14 days in to cycling (fishless) a new 15-gal tank that will host a goldfish at some point. We live in an area with really hard water that also has a high iron content (turns your hair orange high). So, we have a Kinetico water softener. I don't have access to non-softened water so that's what I'm using in the tank.

    After initial set up my pH was steady at 8.0, but over teh last couple of days has creeped up to 8.4. I bought an API GH/KH test kit and tested the water tonight. Here are my questions.
    1. It took 14 KH drops to turn the water from blue to bright yellow. The conversion chart stops at 12. Does this mean the water is unhealthy?
    2. When I put the first drop of GH in, it did not turn orange. Instead, it turned a very slight hint of green. Is this odd? Should it have turned orange first?
    3. Regarding the GH, how green should the water be before you stop adding drops? I stopped at 4 but it was not a bright, solid green like the KH was a bright, solid yellow.

    Currently, my tank shows
    • pH 8.4,
    • ammonia 0
    • nitrites 0
    • nitrates 20.
    • Temp 78.
    I have Caribsea EcoComplete substrate, a few rocks, a piece of driftwood and some live plants that are growing fine (so far).

    Tap water is
    • 7.4pH,
    • 15 KH drops
    • 6 GH drops (107.4ppm?)
    I had planned to do a 50% water change tomorrow in anticipation of adding a goldfish on Sunday. But want to make sure the pH/GH/KH trio isn't wonky.

    Hoping this is enough information.
    Thanks in advance!
    Beth
     
  2. Byron

    Byron Member

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    The API GH/KH test. Add the drops slowly, capping and shaking after each drop. With the GH test, the first sign of green is where you stop; it does not have to be a dark or bright green, just the first tint of green. If this happens with drop 1 without the orange, then your water has a GH of 1 or below. Mine is like this, which is very soft. Same for KH. I find it is much easier to discern these changes when you hold the tube (after adding a drop, capping and shaking, then uncap) uncapped over a piece of pure white paper and look down vertically through the open tube.

    The GH test is only looking at calcium and magnesium which is what normally makes water hard/soft. So iron for example will not register as GH with this test.

    If your natural water is hard, it is likely the effect of the softener than causes this test to show very soft water. Most softeners remove calcium and magnesium by some method. Which brings me to the issue of salt: most do this "softening" by using sodium chloride (common salt like sea salt) to replace the calcium and magnesium salts. Sodium chloride salt will not register as GH either, so the water is technically "softer" due to the removal/replacement of the calcium and magnesium salts, but this does not mean all is OK. It is not, because salt is even worse for freshwater fish. Generally, it is not advisable to use water for fish when the water has gone through a softener.

    The presence of iron is also highly dangerous. This is a heavy metal, and deadly to fish and most aquatic invertebrates.

    To the pH variance. It is likely the tap water test did not out-gas the CO2, so it seemed lower in pH. The 8.4 pH in the tank is probably closer. You can out-gas CO2 from tap water by agitating very briskly a container of fresh tap water, or letting it sit 24 hours before testing. The resulting pH number will then bee more likely accurate. Also, the high KH means the pH is strongly buffered so it is not going to fluctuate in the aquarium from the level in the tap water. This is another clue that the tap water test of 7.4 is most likely in error, but probably due to the dissolved CO2. Testing tank water (assuming not freshly filled) does not require this out-gassing.
     
  3. BMBLSAD

    BMBLSAD New Member

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    This is really helpful. I noticed after I ran an airstone for an hour or so in a bucket of tap water the pH went up to 8.0. Good to know about the GH kit. I can safely say that mine is 1 or less then. I didn't know that about the iron...the softener pulls out a lot of the iron, at least I'm assuming so because my hair doesn't turn orange anymore

    Maybe I should convert over to distilled or RO water before adding a fish. I found this article that offered some guidance on the different waters to use, and it suggested distilled or RO. We do have an RO system, but the filters are mighty expensive and increased use will mean increased filters.

    Thanks again for the input! Most helpful.
     
  4. Byron

    Byron Member

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    That is obviously the out-gassing of the dissolved CO2, so now you know the pH is around 8, and as I said earlier, with the higher KH this is not going to fluctuate or lower in the aquarium.

    On the RO, that is your call and dependent upon the fish you want. If you stay with harder water fish (livebearers, rift lake cichlids, some rainbowfish in general) and can use water not run through the softener, it might work fine. If you intend soft water species, RO is about your only option. Some species are more adaptable than others.

    The problem with preparing water is that you need to do this for every water change. Emergency water changes can be difficult if you don't have sufficient water prepared on hand.

    GH and KH can be lowered by diluting the water with pure water (RO, distilled, sometimes rainwater). It is proportional, so mixing half RO with half tap (initial, not softener water) will reduce the GH/KH by half, and so forth. And the pH may lower along with this, depending upon the final mix and thee organic load.
     

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