New RO membranes contain preservatives. The hour is sjust an estimate.
The proper way to install new filters is to remove all the old filters and membrane then wash all the housings in warm soapy water, rinse well then reassemble everything minus the filters and membrane and run a wek bleach solution through it to disinfect the system. A couple of capfulls of bleach, no more and no less, in the first sediment filter housing is sufficient. Fill the housings and let it stand full for several minutes before flushing it out until the chlorine smell is gone.
Now install only the sediment filter, disconnect the line between the carbon block and the RO housing and stick it in the sink or a bucket. Run this for several minutes to flush the glues and binders out so they do not foul the carbon block pores. Next install the carbon block, or only the first if you have two (which I do not recommend) and again run the system to the drain for several minutes to flush the carbon dust or fines out so they don't foul the new RO membrane. Repeat if you have two carbon or just get rid of one carbon altogether and run a single 0.5 micron carbon block as long as you have an equal sized or smaller sediment filter to protect it.
Install the RO membrane making sure it is seated correctly. Reconnect the line from the carbon to the RO and run the system for a minimum of 3-5 gallons while using your handheld TDS meter to monitor the RO only TDS. Once this drops to about 2-3% of the incoming TDS you are ready to install the DI. Install the new DI and rinse it up for approximately 1/2 to 1 gallon or two to three bed volumes.
You are ready to make water. First check and adjust your new flow restrictor which you should always purchase with a new RO membrane so it is the correct waste ratio for your water conditions. Never assume the waste is correct as it rarely is out of the box. Now while making RO/DI check and record some baseline readings so you have some historical reference to look back on. Tap, RO only and RO/DI TDS, water pressure and temperature and actual measured waste ratio are good to start with. It is also good to know the calcium carbonate hardness of your water which you use to determine what your waste ratio should be set at. Hard water and high TDS need 4:1 waste ratio if you expect the membrane to function properly and last very long. 3:1 works if you have soft to moderately hard water and normal (250 or less) TDS at the tap. 2.5 or 2:1 ONLY works if you have soft water and lower than normal TDS, don't let anyone tell you any different.
And please find a better vendor for your RO supplies who actually understands RO and DI and has some experience in the industry. There are many vendors on the reef forums who specialize in RO, not chemicals which I love BRS for, and have decades and decades of experience and knowledge. BRS needs to stick to what they do best, chemicals.
