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Search results for query: Log10

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  1. dw1305

    Co2 drop checker vs ph measure

    ...Scientific Data">, rather than actual CO2 measurements. This really just reflects the difficulty of <"measuring dissolved CO2 directly">. The log10 nature of the pH scale, and how that relates to CO2 content, is described by @hax47 recently <"Confusion concerning 0dKH and nitrification"> and...
  2. MichaelJ

    Confusion concerning 0dKH and nitrification

    Thanks @hax47 ... Appreciated! I will keep that in mind next time I travel in Transylvania. Cheers, Michael
  3. H

    Confusion concerning 0dKH and nitrification

    It is the Henderson–Hasselbalch equation, which is used to calculate the pH of a buffer: pH = pKa + log10([Base]/[Acid]) Where pKa is the negative base-10 logarithm of the acid dissociation constant. From the equation, one can see, that pKa is the pH value by which the concentration of the...
  4. dw1305

    C02 injection with already low ph

    Hi all, At least I got the broad brush bit right. Please correct. As <"you've already found">, I'm not a chemist and <"I really struggle with this">, what is important is we get the science right and that I can refer back to this the next time I'm hopelessly confused. That was partially why I...
  5. Andy Pierce

    C02 injection with already low ph

    Whilst I certainly agree with the entirety of the sentiment of the post, the above statement is incorrect. pH is (by definition) the negative log10 concentration of protons (hydronium). There is no consideration as to the number or concentration of proton acceptors, other than indirectly...
  6. dw1305

    C02 injection with already low ph

    Hi all, That works, it is <"add a neutral salt"> (usually NaCl) method. This is because pH meters are a <"special type of conductivity meter"> and the salt addition raises the amount of ions in solution (Na+ and Cl-), but these cancel out in terms of pH, which is why it is a "neutral salt"...
  7. MichaelJ

    make ammonium nitrate

    ...1 - say going from pH 6 to 7 increases the Toxic Free ammonia by a factor of 10 for any level of Total Ammonia Nitrogen (TAN)! (following the log10 of pH). A 1 pH spike is quite common for CO2 injected tank during gas-off hours. The trouble with NH4 kicks in around pH 7.5 as it begins to...
  8. dw1305

    260 L planted tank, minimum maintenance

    Hi all, It is, but the problem is that pH isn't a linear scale, it is both a log10 value and a ratio. Have a look at <"pH curves (titration curves)">. If you have tap water that is 8 dKH it will have a ph value of ~pH8, via the <"CO2 ~ HCO3- ~ pH equilibrium"> - <"CO2 and pH: Understanding...
  9. MichaelJ

    PH remains the same when diluting tap with RO- Why?

    ...bit....) The resulting pH pHr by mixing two liquids of pHa and pHb where the fraction of the liquid with pHa is x (percentage/100) : pHr = -log10 ( 1/10^pHa * x + 1/10^pHb * (1-x) ) Say we mix waters 50/50 Container A is pH 6.5 and Container B is pH 7.4. a = pH 6.5 = 1 / 10^6.5 =...
  10. Musicmanryann

    Seachem Purigen Head Scratcher

    Thanks all for this perspective. I guess I am more than a little confused? Getting back to why I am measuring pH in the first place as I am monitoring the pH drop from CO2 as I continue to get it "locked in" as per @Zeus' methodology. It was observed that my drop checker might be a little...
  11. dw1305

    Seachem Purigen Head Scratcher

    ...that you'll read about <"pH stability and buffering are wrong"> The "problem" is really with the pH scale, which is both a ratio <"and a log10 scale">. At pH7 you have an equivalent activity of both <"proton donors (acids) and proton acceptors (bases)">, but pH doesn't tell us anything...
  12. dw1305

    Potassium Carbonate (K2CO3) vs pH ?

    Hi all, Yes, one or the other. Because of the <"log10 nature of the pH scale"> when <"you are around pH 7"> it is any <"minor difference in ratio of proton donor : acceptor"> that changes the pH, so I'd guess that it is possibly the test kit. I always look on pH measurement as a bit like...
  13. dw1305

    Some handy facts about water

    ...in practice is that conductivity meters are a lot more plug and play than pH meters and conductivity is a linear scale, <"while pH is both a log10 scale and a ratio">. If some-one reports a conductivity reading you can be pretty sure it is about right, but you are a lot less sure for a pH...
  14. dw1305

    New to RO dosing question

    ...is never stable, and it doesn't matter">. <"Theoretically RO / DI water should be pH 7">, but in practice it is lower due to dissolved atmospheric CO2, but, because pH is both a ratio and a log10 scale, it is <"pretty much meaningless"> in any water with very few dissolved ions. cheers Darrel
  15. dw1305

    Double checking full EI dosing as per calc

    Hi all, It is, as you approach pure H2O pH becomes <"more and more unstable">, due to the ratio (and log10) nature of the pH scale. This happens <"in nature">, as well as in the aquarium. I think more the point would be that <"changes in pH"> aren't <"necessarily damaging to fish">. cheers Darrel
  16. dw1305

    Lean dosing pros and cons

    Hi all, Yes that is it, it is how the <"drop checker works">. Because pH is both a ratio and a log10 value there <"isn't a linear relationship"> between pH and CO2 value, unless you stay in log10 values. I think a one unit pH drop is always about 30 ppm CO2. I'd guess after that the log...
  17. A

    BBA came back!

    Correct. A 1.0 pH drop is a tenfold increase in acidity since pH is a logarithmic (log10) scale. But all the rest of your reasoning is unfortunately wrong. No. The acidity will increase as CO2 is injected due to the formation of carbonic acid. But there are multiple chemical processes in tank...
  18. dw1305

    Questions regarding biotope setup - BADC 2022

    Hi all, I really enjoyed the video, but he doesn't explain that pH is a ratio, as well as a log10 scale and it is the ratio aspect that means you can go through several orders of magnitude of pH change with very little change in actual ionic composition. This leads him to talk about rapid "pH...
  19. dw1305

    Tannins.

    Hi all, The issue is really the pH scale, it just doesn't "work" as you approach pure H2O. It is because pH is both a log10 scale and a ratio. It is the ratio bit that matters, pH 7 just indicates that there is a balance between protons ~ hydrogen ion (H+) donors ("acids") and hydrogen ion...
  20. dw1305

    Is expensive bio media worth it?

    Hi all, It could well be true and, at the same time, totally, totally irrelevant. It is back to the nature of the pH scale, it is <"both log10 and a ratio">. This means that, in water with <"little buffering">, you can <"get huge pH swings"> from minuscule changes in water chemistry. If you...
  21. dw1305

    New to CO2

    ...30 ppm CO2, because it is based <"upon the assumption"> that there is about <"3ppm CO2 in water">. We also think the reason why dKH is irrelevant (when you have more than about ~4dKH) is because <"pH is a log10 scale"> (you need to read from this post until the end of the thread). cheers...
  22. dw1305

    kH or no kH that is the question....?

    ...at "lights out" with healthy fish, you know that pH fluctuation isn't the issue. The problem is with pH as a measurement in that it is both <"log10 value and a ratio">. You can't extrapolate between hard water and soft water Rather than get hung up over pH levels I just look at changes in...
  23. dw1305

    Perplexed about extreme TDS readings

    ...much about pH, because as you approach pure H2O (like your RO) pH becomes of <"very limited value">. This is because pH is both a ratio and a log10 value. I tend not to worry too much about pH in soft water, because it can never be stable and small changes in water chemistry cause large...
  24. dw1305

    Do I need GH/CH?

    ...water. I should have said I agree with Clive. There is more explanation in the linked threads, but once you know that you can raise and lower the pH values by one unit (and pH is a log10 scale) using CO2, without damaging your fish, you know that there is more to it than just pH. cheers Darrel
  25. dw1305

    Guide to TDS

    ...the chance <"to sell you a product">. While conductivity is a really nice straight forward measurement, pH isn't, mainly because it is both a log10 scale <"and a ratio">. When you have more than about 2 dKH your "resting" pH will go up to pH7.8, but it is easy to reduce because you have...
  26. dw1305

    pH tester

    ...where you already have a good idea what the pH is likely to be. The problem is really that pH is a very strange measurement, it is both a log10 scale and a ratio. If you have hard, salts rich, water then the pH will always be about pH8, and your pH meter will tell you that, the same applies...
  27. Zeus.

    DIY Fertilizer Formula Recommendation

    :eek::woot::clap::clap::clap: and thank you for sharing the details :thumbup:. I have to admit that my ferts do go a bit cloudy near the end. Do like the idea of keeping the fert in the fridge, no room in fridge but do have space in freezer in garage, think that should do the trick as well !
  28. X3NiTH

    DIY Fertilizer Formula Recommendation

    ...Acid, I was tipping teeny little spoonfuls beyond the initial dose and not seeing much of a pH shift until it dawned on me that pH is a log10 function and I would need approximately a 10x weight increase to shift one point in pH, so I stopped addition deciding I'd rather save the Acid than...
  29. jaypeecee

    Why Advise A 1pH Drop?

    ...A drop of 1 pH unit is actually an increase of 10 in the ratio of H+:O-H ions, when you have a pH drop of 1 unit you have: 3ppm x 10 (1 as log10) = 30ppm CO2" The initial CO2 concentration in the tank water is very likely to be in excess of 3ppm because, overnight, the plants will have been...
  30. dw1305

    Why Advise A 1pH Drop?

    Hi all, I don't claim any proper understanding of this, but I think that is the point. The dKH doesn't remain constant because you have the pH ~ CO2 ~ carbonate equilibrium which changes as you add CO2. Once you have more than ~4dKH of carbonate buffering the pH will always equilibrate to pH...
  31. dw1305

    Question about PH controller.

    Hi all, I'd do that. You'll probably find a bit of drift at both pH4 and pH10, but not a lot. Because pH is a log10 scale as you move away from pH7 you tend to get a <"more "accurate" reading">. I like the <"instruction page"> link for the WEIPRO, nice and clear. That would be my worry. I'm...
  32. dw1305

    What's the deal with kH/Alkalinity?

    ...etc. You don't need to raise the dKH. There are a number of difficulties with pH measurement and interpretation, pH is both a ratio and a <"log10 scale">. Stable pH only exists in very heavily buffered water. As you approach pure H2O pH becomes less and less meaningful. In soft waters pH...
  33. dw1305

    pH Probes

    ...value, and the fact that the value might need some interpretation.. You tend to get more uncertainty around pH7, it is because of the <"log10 nature of pH as a scale">. The simple answer is that small changes in water chemistry cause large changes in pH around pH7. If you move into the...
  34. dw1305

    Ro Water Ph

    ...for less than 50microS (~30 ppm TDS), which may well be about 95:05 RO and Tap. The problem is with pH as a measurement, it is the negative log10 ratio of the activity of H+ ion acceptors (bases) and donors (acids). As you get towards pure H2O pH becomes less and less meaningful or stable...
  35. dw1305

    Ph pen recommendation

    ...read consistently below pH4, and you need to add a lot of bases to neutralise the acid. The problems come because pH is both a ratio, and a log10 scale. When you are looking at the CO2 ~ HCO3- ~ CO3 ~ pH equilibrium you are looking <"at a buffered system with relatively small changes in the...
  36. dw1305

    amount of C02 required based on KH / mixing RO with tap water

    Hi all, Ed I'm not sure, it is back to needing a chemist, but think it is because pH is a log10 scale, and if you plot an exponential curve as log10 values you get a straight line. It is this bit and links (from <"Question about pressurised CO2...."> cheers Darrel
  37. dw1305

    Ph Meters

    Hi all, The problem is that pH is a really strange measurement, it is both a log10 scale and a ratio. As you move towards pure water pH becomes less and less meaningful as a measurement. cheers Darrel
  38. Manuel Arias

    Drop checker color relation to KH question

    ...= 10^(-10.33) And with [HCO3-] = 0.00642, we can solve the equation and get [H+]: [H+] = 4.9215 * 10^(-9) M that translated to pH as pH = -log10([H+]) = 8.31 Having [H+], we can now determine the amount of dissolved CO2, as [H2CO3*] = [H+] * [HCO3-] / K1 = 6.304 * 10^(-5) M As...
  39. Manuel Arias

    Is this too much CO2?

    Hi again, I agree with Darrel, especially because CO2 diffusion takes some time, so colours in drop checker are always with a lag respect to changes in the tank. This, in my opinion, the problem with this system: It is assuming that you have a dkH of about 18-20 in water (about 200 mg/l of...
  40. dw1305

    Is this too much CO2?

    ...water being 3ppm CO2 (which is probably a fair estimate for most tanks) and a one unit pH drop then takes the CO2 content to 30ppm CO2 (pH is a log10 scale). Because it is a log10 scale if you had a pH drop of 2 units you would have added <"300ppm CO2">. I'm not a CO2 user (nor ever likely to...
  41. dw1305

    Aquasoil pH increase

    ...30ppm of CO2 you get a drop of about 1pH unit, it doesn't matter how many HCO3- ions you have (pH drop is independent of dKH, because pH is a log10 scale). Calcium carbonate is insoluble in water, but in water with carbonates present the small amount of CO2 (that goes into solution as H2CO3)...
  42. dw1305

    So what does this tell me?

    Hi all, I think pH is a really difficult concept to get your head around, it is both a ratio and a log10 scale. You read this a lot on other forums, but it isn't true in all situations, in fact you will always have fluctuations in pH in soft water. These occur in the wild as well as our tanks...
  43. J

    Question about pressurised CO2 and water disturbance

    See? I wouldnt have said it in a million years, even though I think I understand it cause Ive done some chemistry in the past:lol:. So just to recap Darrel. Could we conclude that "pH drop" is independent of KH? Even if its not exactly 1 unit of ph. In other words you need the same pH drop no...
  44. dw1305

    Question about pressurised CO2 and water disturbance

    ...But I think I've got it. Assuming that the "pH drop of 1" for ~30ppm CO2 is right, it is because it is a buffered system, and pH is a log10 scale. The drop in pH is determined only by the concentration of CO2 in the water. In the same way a reserve of HCO3- (dKH) will maintain pH at ~pH8...
  45. dw1305

    Help me choose a pH meter

    ...fails it will give you a ball park figure, with certain proviso's. The problem for all pH measurement is the pH scale itself, because it is a log10 ratio it works very well in highly buffered acid, or alkaline, solutions, but around pH7 (10-7 H+ & OH- ions) or in solution with few ions, it...
  46. dw1305

    Mystery pH rise?

    ...actually very little difference chemically between pH7.2 and pH7.4. This is because of the nature of pH, pH is a very strange measurement on a log10 scale. The neural point (neither acid no base) is at the activity of 10-7 H+ ions (and 10-7 OH- ions), at pH8 you have 10 times less H+ ions...
  47. dw1305

    Test Kits

    ...dissolved carbonates. I think pH is a very tricky measurement, mainly because you need a measure of dKH before you can interpret it, it is a log10 scale, and it is ratio so tells you nothing about amounts. Really you are back to the colour printer again red (acid) or blue (alkaline) fine...
  48. Deano3

    ADA 60F iwagumi

    Well firstly I am glad you did the calculations lol and I now understand what the ph is and how the co2 influences it, so from gas on to lights on should drop from say 6.6 to 5.6 my test kit is not very good and doesn't even go that low but if goes yellow I will know, the gas already comes on 3...
  49. ceg4048

    ADA 60F iwagumi

    ...simple number. That simple number is the number of free Hydrogen ions (H+) in the water. The calculation of pH goes something like this: pH = log10[H+] Knowing that the pH is 6.6 you can solve the equation for the H+ count: [H+] = 10-pH [H+] = 10-6.6 [H+] = 2.5 X 10-7 That's the number of...
  50. P

    Reborn

    Not many have such low uS tank water. Ferts also add a lot. So my tap is pretty soft, but the ferts contribute about 150-200 uS, so I'm at about 250-300. The curve drops offs real fast as you approach zero KH. But..........this just means you cannot measure it directly with pH/KH. You can do...
  51. dw1305

    Reborn

    ...pH becomes problematic as you approach pure H2O (or 0dKH). Around pH7 measurements are always likely to vary, because pH is both a ratio and a log10 measurement, and at pH7 (10-7 O-H and H+ ions) small changes in ratio lead to large changes in pH (this is what Tom alludes to earlier in the...
  52. dw1305

    calibrate at 7ph first then 4?

    ...4 - pH7 you use pH4 followed by pH7, if the pH is above pH8 you use pH7 and pH10 buffers. You start with pH4 (1 x 10-4 H+ ions). Due to the log10 nature of the pH scale you should be able to calibrate the meter exactly to pH4, pH7 is more problematic as you have equal numbers of OH- and H+...
  53. dw1305

    pH probe calibration, question

    ...pH meters: Around pH7 you will always get some movement, the difference between pH7.01 and pH7.05 is small in H+ ions, we are back to the log10 pH scale and this may just be a temperature difference. We have about 50 pH meters in the lab from £100 dip meters up to bench meters costing...
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