Kent ro/di unit used

Found a Kent unit local for 40 seller said it's 1 year old. Wanted to know if it's a good buy? Not sure on gpd but he said he had it for his 150g set up. Thanks

 

$40 is a fair price, heck the filtration canisters/RO housing and line fittings are worth 40 or 50 bucks alone. you will probably need to replace all filtration media including the membrane. make sure to find out the GPD so you can match the flow restrictor to your new membrane. Just my $.02

 

The membrane isn't suppost to be switched out every two years???

 

There are a lot of factors that you have to take into consideration when talking about water filters and mambranes such as:
Tap water quality
How much water has gone through the membrane
If the unit has a flush kit

For me it really depends on how much water has gone through it, and how many pre filters it has. if it was used for a larger tank 90gal+ i would recomend replacing it yearly if it has no flush kit. Most reputable shops that have RO/DI water to buy replace their membranes every 6 months to a year. To be on the safe side when i buy anything used i break it down give it a good cleaning and replace any parts that go bad over time. And who knows somone could say 1 year and it actually has not been changed in 2 or 3 years.

 

Seems I'm better of buying a new one. Seems it will be cheaper in the long run.

 

If you go to Bulk Reef Supply you can build whatever kind of RO setup you want it to have and the prices are pretty good for what you get too.

 

It can be tough buying used units unless you know the person and history of the system.

The membrane is probably OK since its only a year old but you never know if it has been allowed to dry out or has had hot water run through it, both of which ruins a membrane. The prefilter and carbon block get changed out every 6 months so at a minimum they would need replacing for around $30. The DI resin is probably in need of replacement too and thats another $15-$20 so now you are at $90 on your used purchase. If the membrane does need replacing thats another $30 plus $5 for a flow restrictor.
Add to that a TDS meter and an inline pressure gauge since its impossible to own a RO/DI and know how it is performing without them, another $50-$60.

You now exceed the cost of a new system and you still have used housings and fittings.

Look at the CSPDI here for $199 including everything listed above plus its 90 GPD, high rejection and comes with a warranty backed by one of the oldest names in the business.
Untitled Document

Other good options include the 75 GPD Premium found here:
www.buckeyefieldsupply.com

or the reefkeeper found here:
www.melevsreef.com

Forget the flush kit, all it does is lighten your wallet and has no proven documented value. If you want something useful go with a DI bypass so you can use RO only water or a dual vertical DI, those actually do something.

Membranes can last up to 10 years or more as long as you use quality low micron replecament prefilters and carbons such as the 0.5 micron absolute rated like Spectrapure and you disinfect the system at least annually. Its the ebay quality filters that wear a membrane out since many are about as effective as a screen door when it comes to filtration. I am going on 3 years with my current membrane and its still at 99.35% rejection rate before DI.