Ok, with Florian's last post in mind under "bacteria from RO membranes", how many of you culture your output of your pretreatment, as in the water going to your RO systems? Do you think is necessary? If so how often? What level would be acceptable? Unacceptable? What do you do to correct it if you do have an unacceptable level?

I do not do it on regular basis but we did do for a short period of time trying to resolve a bacteria problem we were having. Before the the carbons you have the chloramines in the water and bacteria levels should be low but I'm not sure if they should be 0. After the carbon tanks before the ro the chloramines have been removed and the potential for bacteria there goes up. What we were looking at was trying to figure out maybe how much bacteria we had going in then tried to figure out what 1-2% of that was and see if that is what was coming out the product output.

We do not culture pretreatment because we don't have the answers to all of guest 1's questions.