reverse osmosis

For sale are two used Norwesco poly tanks in very good condition. They were used for a saltwater mixing station for my aquarium and were kept indoors since I bought them. One was used for RODI water and the other for saltwater. The RODI one has a 1/2" hole drilled near the top on one end that...

Can i hook this up to my hose and use it to do water changes directly? Hoe many gph will it put out? What do I need to get besides the filter to do that? https://www.amazon.com/Aquatic-Life-2-Stage-Filtration-Sediment/dp/B01HRDE238 Thanks!

I've been looking at starting up a Reverse Osmosis System to try and purify my tap water because I'm starting to think that my tap water contains high levels of nitrates and that is why I'm having a hard time keeping nitrates down in my 125 gallon setup. I've been looking at the RO unit that...