SantaMonica
Well-known member
Preventing Bacteria Growth On RO Membrane
I need an RODI system for once-a-month use on a 90. I'm changing 30 gal saltwater a month, and I'm topping off 30 gal kalkwater a month (one gal/day), so the total RODI needed is 60 gal per month. The tank is in an office, and other than feeding (which can be done by others), I only want to have to attend to it monthly. I need to fill up a 30 gal container with RODI so I can make saltwater, and then fill up another 30 gal container with RODI so I can make kalkwater. The saltwater will then be used for waterchange, and the kalkwater will be used for auto topoff throughout the month. Problem is, I've read about bacteria growing on (an in) the RO membrane if the RODI unit is not used more than once per week (thus destroying the membrane). Well, I can't use it once a week because I'm only there once a month.
I know many people solve this by using a water level-control in their freshwater holding container, and from there the water goes to a kalk reactor which then goes into the sump via a float switch at the sump. This does keep bacteria from growing on the RO membrane, since the RODI unit operates on-and-off periodially as the level controller keeps the freshwater container filled. Problem with this setup is that a separate kalk reactor is needed, and, TDS creep occurs as the freshwater container auto-fills itself.
My design, however, takes kalkwater from a 30 gal freshwater container (that I fill up monthly and add kalk) and puts it into the sump as needed (via a float at the sump), thus avoiding a separate kalk reactor, and avoiding TDS creep because I'm only using the RODI unit once a month (and when I do use it, I manually discard the initial output of the RODI which gets rid any creep that there is.)
The problem to be solved with my design is this: What can I do to stop the bacteria growth that will build up on the RO membrane as it sits there unused for a month?
I need an RODI system for once-a-month use on a 90. I'm changing 30 gal saltwater a month, and I'm topping off 30 gal kalkwater a month (one gal/day), so the total RODI needed is 60 gal per month. The tank is in an office, and other than feeding (which can be done by others), I only want to have to attend to it monthly. I need to fill up a 30 gal container with RODI so I can make saltwater, and then fill up another 30 gal container with RODI so I can make kalkwater. The saltwater will then be used for waterchange, and the kalkwater will be used for auto topoff throughout the month. Problem is, I've read about bacteria growing on (an in) the RO membrane if the RODI unit is not used more than once per week (thus destroying the membrane). Well, I can't use it once a week because I'm only there once a month.
I know many people solve this by using a water level-control in their freshwater holding container, and from there the water goes to a kalk reactor which then goes into the sump via a float switch at the sump. This does keep bacteria from growing on the RO membrane, since the RODI unit operates on-and-off periodially as the level controller keeps the freshwater container filled. Problem with this setup is that a separate kalk reactor is needed, and, TDS creep occurs as the freshwater container auto-fills itself.
My design, however, takes kalkwater from a 30 gal freshwater container (that I fill up monthly and add kalk) and puts it into the sump as needed (via a float at the sump), thus avoiding a separate kalk reactor, and avoiding TDS creep because I'm only using the RODI unit once a month (and when I do use it, I manually discard the initial output of the RODI which gets rid any creep that there is.)
The problem to be solved with my design is this: What can I do to stop the bacteria growth that will build up on the RO membrane as it sits there unused for a month?
