Fresh saltwater is necessary to do monthly water changes and fresh RO/DI water is needed to replenish for evaporation. So I would drive every week to my local fish store (LFS), and buy RO/DI (Reverse Osmosis/ DeIonized) water.
Until one day i decided to make room in my garage and buy an RO/DI system and setup a saltwater mixing station at the house. My first obstacle was trying to find the space to store RO/DI filters, water storage containers, and saltwater mixing buckets. After some thought, I decided to use (2) 32 gallon BRUTE trashcans and will mix up about 25-30 gallons at a time.
I started the saltwater mixing station build with a stand that i would make out of (5) 2 x 4's and one piece of pre cut plywood at 48" x 24" x 1/2 inch.
After the stand was built, i set the BRUTE trashcans side by side and began to drill and pipe. I installed a auto shut off float valve to keep the system from over filling my holding container and with use of a pump, union valves and some ball valves to adjust the flow water, i was on my way to making the hobby a lot easier.
Every build you will read will always talk about unions. Use as many unions as you can. They are more pricey but it’ll be worth it when you have to take out a dead pump or pipe and replace/clean it. They will make it easy to unhook everything as well so you can take it down for cleaning or a move!
The BRUTE trashcan to the left will hold my RO/DI water and by opening the valves and plugin in the pump, water will be fed to the barrel to the right. Once the valves are closed and salt has been added to the BRUTE trashcan on the right, valves will be opened on the saltwater side, that will circulate the water through the pump and back into the BRUTE trashcan for mixing. I also used a internal aquarium filter pump to circulate the water and heater to keep the temperature at 78 degree.
RO water will automatic refill the BRUTE trashcan on the left, until it hits the auto shut off valve, so that water is ready for use. When i am ready for fresh saltwater or RO water all i need to do is turn the ball valve on either side to get the water that i need.
Why use RO/DI (Reverse Osmosis/ DeIonized) water?
When you have invested your time and hard earned money into this hobby, water changes with tap water is really not a good option. The main reason is that you are not able to control the parameters in tap water. There is no easy way to determine every mineral and chemical that comes out of our tap, nor in what quantities. To avoid using tap water most aquarists will start with RO/DI (Reverse Osmosis/ DeIonized) water.
RO/DI water is any water that has been purified of any minerals or chemicals that occur naturally or that have been added by the water company. RO/DI filters will take all the Total Dissolved Solids (TDS) out of the water and make it safe for your aquarium livestock.