Our new RO/DI line comprises of two distinct lines with the Value series and the Universal series. I am going to make this super simple for everyone. Most reefers have no idea what is in their water supply so if you just want to know you're covered and want the best filtration availablee, go with the Universal series and you'll know you're covered. We call it a Universal system because it is an ideal solution for chlorine and chloramines, well water and the common contaminants aquarium owners are concerned about. If your city has fairly clean water to begin with, or you are looking to save a few bucks right now but want to keep the upgrade paths open get the Value series which is solid option for most reefers and completely upgradeable if you ever wanted to add another carbon block or DI canister at a later date. The Value line also uses a universal carbon block so you are covered with both common water disinfectants; chlorine and chloramines. The biggest difference is with a single carbon block you will have the replace the filters more frequently, which makes it a bit less cost effective over the long run. Both the Universal and Value series come in three models. A basic, a plus and water saver plus. The basic models have the same filtration qualities as the other models in their own series. There's almost no difference in water quality between the basic models and the plus or water saver plus just additional accessories which can make the system easier to use, last longer, use less water or produce water faster. The Plus models both include the same three upgrades; a flush kit for the membrane which allows you to open a valve to clean the membrane and extend its life, a pressure gauge which helps insure proper operating conditions as well as identify when the pre-filters are clogged with sediment and need to be changed. Both the plus models also include a TDS meter which measures the total dissolved solids and how the system is performing. A TDS meter is one of those things almost everyone eventually buys because we all want to know how our systems are performing. The Value plus has a dual stage TDS meter which measures the RO system performance as well as the DI or product water stage. The universal plus comes with a three stage TDS meter which measures the RO system as well as after both DI stages. These three accessories are very popular add-ons and why the plus models are easily our biggest sellers. The third model in both series is the water saver plus. Like the other plus models it they include the flush kit, pressure gauge and TDS meter but also includes a 150 fifty gallon per day water saver upgrade kit. This kit has three major advantages. First it doubles the output of the system from seventy five gallons per day to one hundred and fifty. Second it effectively cuts the waste to product water in half and saves a ton of water, third by reducing waste to product water ratio the system effectively doubles the volume of water you can produce on a single set of sentiment and carbon block pre-filters. This advantage is particularly valuable if your city uses chloramines in the water supply because doubling the filter life here is going to save a significant amount of money over the year.