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  • #16
    You have to be careful anywhere there's karst limestone in the water table. Sounds like that might be surface river water, not well water.
    3.5KH is likely surface, not well. Might be a little non carbonate hardness in there. Still, not likely more than 1-2 degrees.

    If you have a wet/dry, 66 ppm seems fine.

    If not, etc, maybe 40-45 ppm might be the limit.

    Cranking the surface current will help maintain a higher CO2 threshold also if you do not have a wet/dry.
    www.BarrReport.com

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    • #17
      I actually just retested and came up with 4.5 dkH. I tend to believe the 4.5 since its what my tap water is at....doesn't really water matter just gives me a reference point.

      I'm part of the Miami Valley Buried Aquifer. I'm a bit too far north. I have a few friends that are in the limestone one. I know my ex-gf was in it.

      Yes, I have a wet/dry sump and I have a vortech at the surface making waves. I think the 66 ppm will be fine but will start lower and work my way up slowly.

      Off-topic but have you measured your 180 dissolved oxygen? I know you said you ran it at 60-70 ppm CO2 and the fish were fine. I have a LaMotte test kit for dissolved oxygen and wanted to compare.

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      • #18
        It ran consistently at 100% with the lights off all the time.
        During the lighting period, it rose to about 125-130%.

        This was at about 84F, so the ppm is about 7.7 ppm to about almost 10 ppm, a jump of about 2 ppm

        The canister set up never got to 100% except during the light cycle and then only about 1 hour or so.
        So the claim was 1-2 ppm increase in O2 for all my tanks that were canister that got converted to Wet/drys.
        www.BarrReport.com

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        • #19
          Along those same lines as CO2 changing as you go to the higher concentrations, the temperature also plays a huge difference with metabolism of fish, and the ambient O2.

          84F( or about 28.9 C) the O2 = 7.6 ppm.
          At say 70F(about 21 C) the O2 is nearly 9 ppm.

          So you have 20% higher O2 ppm and you do not need a heater.
          Plenty of O2, slower rates of growth, less energy cost.

          This can make a huge difference in the aquarium.

          Say you just want some Amano shrimp, CRS, RCS etc, and say White clouds, then this is a great way to have a planted tank.
          68-72F seems to do very well for most species.

          Algae and dosing are much easier to manage.
          www.BarrReport.com

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          • #20
            Thanks, that makes sense.

            Otos/amano's are my cleaning crew. Looking into getting a couple unique plecos and than probably a shoal of tetras (or something that won't bother the shrimp). Once I figure out the fish exactly I can fine tune the temperature.

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            • #21
              I haven't really tested my tank in a long time and after having problems with a few plants showing signs of co2 deficiency I decided to test tonight. Now I knew I had high kH but after testing tonight I think I might need to start mixing ro water with my tap.

              Here is my parameters:

              kH: 12
              gH: 5
              pH: 6.8

              According to the charts I have 57.1 ppm of co2. I have a wet/dry and what I would consider ample surface agitation and my fish never show any signs of stress from the co2. I quit using my drop checker for reference a long time ago as it is always bright yellow by the end of the day but for some reason I feel that I'm not getting enough co2 into the tank. I have tried 3 different diffusion methods not a one which I have settled on yet. I will not go back to the needle wheel pump feeding right into the tank as the micro bubbles are not to my liking. Most recently after running dual venturi method off my reactor I tried running the reactor post needle wheel pump but didn't notice much of a change. Will lowering my kh by mixing with r.o. water be a smart decision or am I fine just leaving it where it is? I would love to be able to keep rotala macrandra but have had no luck with that plant and assume it doesn't like higher kH. Ideally I think a kH of around 6-8 would be better.

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              • #22
                Worth a shot to drop the KH to about 3-4, you should see some differences.
                You'll need to add the GH booster however.

                When is the pH taken?

                Also, the higher KH's, the more possible error you have with KH.
                And the difference in 1 degree of KH at say 8 vs 9 KH is a lot of CO2, vs KH of 1 vs 2 degrees as you get more and more CO2 into the system.

                Folks need to know that as you approach the upper bounds with the CO2 dosing...........with fish, that it gets more touchy. It's not the same at lower levels of CO2. 0.1 pH change is only a 2-3 ppm at 15-20 ppm, vs say 8-10 ppm once you are up in the 40-50 ppm's (might not be exact, but should be relatively close)
                www.BarrReport.com

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                • #23
                  Calculating CO2 Values Not on KH/CO2/pH Chart

                  Looks like for a given KH, the new CO2 ppm, (CO2_NEW(pH_NEW)) can be calculated by taking the given CO2 ppm: (CO2_GIVEN(pH_GIVEN))*10^((pH_GIVEN) - (pH_NEW)), where pH_NEW<pH_GIVEN.

                  1. Choose a KH.
                  2. Pick a pH value (pH_GIVEN) and it's corresponding CO2 ppm, CO2_GIVEN(pH_GIVEN).
                  3. The new CO2 value at the "new" pH is just the "given" CO2 value times the "given" pH minus the "new" pH raised to the power of 10.

                  For example, at KH = 5, CO2 @pH 8 = 1.5 ppm, @pH 7 = 15 ppm, @pH 6 = 150 ppm, and @pH 5 it should be 1500 ppm.

                  This seems to work for a given KH no matter where you start/"given" or finish/"new."

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                  • #24
                    Originally posted by Detrius Maximus View Post
                    Looks like for a given KH, the new CO2 ppm, (CO2_NEW(pH_NEW)) can be calculated by taking the given CO2 ppm: (CO2_GIVEN(pH_GIVEN))*10^((pH_GIVEN) - (pH_NEW)), where pH_NEW<pH_GIVEN.

                    1. Choose a KH.
                    2. Pick a pH value (pH_GIVEN) and it's corresponding CO2 ppm, CO2_GIVEN(pH_GIVEN).
                    3. The new CO2 value at the "new" pH is just the "given" CO2 value times the "given" pH minus the "new" pH raised to the power of 10.

                    For example, at KH = 5, CO2 @pH 8 = 1.5 ppm, @pH 7 = 15 ppm, @pH 6 = 150 ppm, and @pH 5 it should be 1500 ppm.

                    This seems to work for a given KH no matter where you start/"given" or finish/"new."
                    Yes, pretty much........UNLESS.............can you think of several examples where this will no longer work well? I can think of 3 REAL examples.
                    www.BarrReport.com

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                    • #25
                      Originally posted by Detrius Maximus View Post
                      Looks like for a given KH, the new CO2 ppm, (CO2_NEW(pH_NEW)) can be calculated by taking the given CO2 ppm: (CO2_GIVEN(pH_GIVEN))*10^((pH_GIVEN) - (pH_NEW)), where pH_NEW<pH_GIVEN.

                      1. Choose a KH.
                      2. Pick a pH value (pH_GIVEN) and it's corresponding CO2 ppm, CO2_GIVEN(pH_GIVEN).
                      3. The new CO2 value at the "new" pH is just the "given" CO2 value times the "given" pH minus the "new" pH raised to the power of 10.

                      For example, at KH = 5, CO2 @pH 8 = 1.5 ppm, @pH 7 = 15 ppm, @pH 6 = 150 ppm, and @pH 5 it should be 1500 ppm.

                      This seems to work for a given KH no matter where you start/"given" or finish/"new."
                      Yes, pretty much........UNLESS.............can you think of several examples where this will no longer work well? I can think of 3 REAL examples.
                      www.BarrReport.com

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                      • #26
                        The chart is very helpful. Can the amount of CO2 be improved by adding more excel rather than CO2 dosing?

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                        • #27
                          No, simply because Excel is no CO2. It might help a bit in low CO2 applications, but can never replace it.
                          It's more an intermediate method between CO2 and non CO2 in the aspect of plant growth.
                          regards,
                          dutchy.

                          My 2011, 2012 and 2013 AGA aquascaping contest entries:
                          http://www.barrreport.com/album.php?u=21013

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                          • #28
                            Originally posted by Tom Barr View Post
                            Yes, pretty much........UNLESS.............can you think of several examples where this will no longer work well? I can think of 3 REAL examples.
                            The chart assumes any changes in pH are due solely to the addition of CO2 gas into the system and the KH is constant. So...

                            Immediately following a large water change...

                            1.There would be a dynamic shift in the tank pH where
                            wood/organic material releases acids to lower pH. This effect tapers off as the wood ages.


                            2.There would be a KH increase if carbonate sources dissolve (shells, limestone) and absorb H+, lowering [H+],
                            thus raising pH. This scenario is less likely (hopefully!) in freshwater systems with CO2 dosing since free [CO2]g decreases
                            with increasing pH. A wise hobbyist would eliminate this scenario.

                            Actual free CO2 levels in a well-maintained, mature tank (wood has been submerged for a long time) with non-carbonate rocks would more closely track/match the CO2 levels as predicted on the CO2/pH/KH table.

                            Oh, and I just noticed a linear relationship going DOWN the chart. Holding pH constant, the ratio of any two KH values equals the ratio of the associated free CO2 values.

                            For example, @pH = 7.0 ---> KH4/KH16 = 0.25 and CO2(KH4)/CO2(KH16) = 12/48 = 0.25.

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                            • #29
                              Is there a chart for KH in the 20's lol? I've got 18 out of the tap and 21 in the tank. Ph 7.8 in the morning. I can get it to about 6.2 but fish gasp, I back off to 6.6 as I have had things fail and had build up of CO2 in the past. I leaving a little wiggle room at 6.6 and fish and plants look happy.

                              My drop checker with tank water in it is dark green at this point. (I know, I know I'm supposed to use 4 dkh RO but if it is calibrated with tank water and know what colors are bad, I guess It shouldn't matter). I am in central Indiana on a well with old copper pipes (Toms Favorite time for an RO unit.

                              Anyways back to the thread topic. That chart indicates my CO2 is 150+. Definitely fools carbonate in my tank.
                              May your arrows fly straight and your aim be true,

                              Ben

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                              • #30
                                Is there a chart for KH in the 20's lol? I've got 18 out of the tap and 21 in the tank. Ph 7.8 in the morning. I can get it to about 6.2 but fish gasp, I back off to 6.6 as I have had things fail and had build up of CO2 in the past. I leaving a little wiggle room at 6.6 and fish and plants look happy.

                                My drop checker with tank water in it is dark green at this point. (I know, I know I'm supposed to use 4 dkh RO but if it is calibrated with tank water and know what colors are bad, I guess It shouldn't matter). I am in central Indiana on a well with old copper pipes (Toms Favorite time for an RO unit.

                                Anyways back to the thread topic. That chart indicates my CO2 is 150+. Definitely fools carbonate in my tank.

                                Ben
                                May your arrows fly straight and your aim be true,

                                Ben

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