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I have a similar problem, please see the attachment. Thanks As_pH=6.rea

Hi Brian, Then, How do we input the concentration in Gss ? Now we have the total concentration of Se, but the species can be selected in the basis species were SeO3--, SeO4-- and Se-- . Regards Tianwei

Hi Brian, Thanks, I will contact with the sales department. In addition, I am a little confusing with this example discussed here. As we knew, when Logk>0, the reactions will occurs spontaneously, however, when Logk < 0, the reactions will not occurs at normal conditions. As for Eq.1 above, its logk <0 which can be directlly got using Rxn, then it seems that it doesn't make sense to use it here. Also, I think that Rxn is a very convenient tool by which we can get the Log k of a reactionand easily to determine if the reaction will be happened . Am I right ? I will be very grateful if you could give me some advice on my above qustions. Many thanks and best regards Tianwei

Hi Brian, I got it, Thanks a lot. Tianwei

Hi Brian, Also, I need to update the GWB from 9 version to 10, What should I do next ? Thanks Tianwei

Hi Brian, I attached the script file for tracing the reaction path. As I said before, I could not get the same results like Fig.15.8 in book 'Geochemical and Biogeochemical Reaction Modeling' written by Craig M. Bethke. I am confused, could you tell me why? Best regards Tianwei Ch15_pyrite-modified.rea

Hi Brian, I am a little confused about definition on 'component' and 'basis species' in GWB. What's the differences between them? Regards Tianwei

Hi Tom, How to convert the total As concentration to the arsenic basis species? Since, usually ,the data we get from labaoratory is the total concentration. Thanks Tianwei

Hi Brian, Thanks for your quickly reply. For your replying to question 1, I need to think it over, it was really complicated. For your replying to question 2, I know this and i run the model successfully, but the result (the graph) I got was different from that in tutorial(in "using GWB"), i wonder if my input script file is the same as yours, could you send me the input script file you used in tutorial (part "How do I add a reaction trace "in "Using GWB")? or tell me which file was that you used in install directory. Regards Tianwei

Hi Brian, It seems the reaction described by the eq.1 was not spontaneous, because of its logk<0 which could be directly got by Using Rxn, Thus, is there any sense using eq.1 to calculate pyrite oxidation? Regards Tianwei

Hi, I have three simple questions as follows: 1. How can I model Zero Valent Iron in REACT?(Since there only Fe2+ Or Fe3+ that could be selected in basis species) 2. How do I add reaction trace? I cannot get the results like that from the tutorial(in "Using GWB"), I did not know which input file was that you used in REACT. 3 What does "Fe(OH)3(ppd)" mean? Thanks a lot Tianwei