Also bear in mind that the more water you use to flush the carpets through, the less chemical you need as a rinse.
I use Chemspec Liquid High Heat as a rinse in my TM and I dilute it 1:50 in the chemical jug, running it at about 3GPM. Not sure what dilution that works out at in actual use but it uses a very modest amount of product, but does the job when needed. John Kelly will tell you how much I order per year better than me! But I think I replenish the 1 US gallon container about every 6 weeks or so.
I mostly use either M-Power or HD from Solutions as pre-sprays so normally don't even use the rinse, but when using stronger stuff like powerburst or ultrapac the high heat does a great job, both as an extra "kick" to the cleaning and to reduce the pH. (I have tested with pH test paper after rinsing

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