RODI Help

trying to figure out what filters I need to buy to make this unit work. Also want to upgrade it to a 100 GPD if possible. here is a pic,



the pressure gage is toast and the filters have never been replaced in the 4 years I have had it. the other option is to buy a new one but there 180+ for a comparable model so It would be nice to make this one work.

 

At a minimum you will spend around $85-$120 to get that unit back in shape, $36 for a 90 GPD high rejection rate RO membrane, $6 for a matched flow restrictor, $18 for an economy 1 micron sediment filter and carbon block kit or $27 for much better quality 0.5 micron filters, $15 for a throw away DI filter like you have now or $48 for a true 10" vertical refillable DI canister and cartridge with fresh resin and a built in dual probe TDS meter to monitor it and $11 for a replacement pressure gauge.

For $125 you can have a new system with all of that minus the TDS meter and that needs no work.
http://spectrapure.com/Refurbished-90-GPD-RODI-System

You don't want the Dow Filmtec 100 GPD membrane unless it is specifically the new HR version which most do not sell.

 

At a minimum you will spend around $85-$120 to get that unit back in shape, $36 for a 90 GPD high rejection rate RO membrane, $6 for a matched flow restrictor, $18 for an economy 1 micron sediment filter and carbon block kit or $27 for much better quality 0.5 micron filters, $15 for a throw away DI filter like you have now or $48 for a true 10" vertical refillable DI canister and cartridge with fresh resin and a built in dual probe TDS meter to monitor it and $11 for a replacement pressure gauge.

For $125 you can have a new system with all of that minus the TDS meter and that needs no work.
http://spectrapure.com/Refurbished-90-GPD-RODI-System

You don't want the Dow Filmtec 100 GPD membrane unless it is specifically the new HR version which most do not sell.

 

What about something like this?

http://www.ebay.com/itm/171074950539?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I've seen this and been tempted but for the same price I like the Spectrapure more because I've heard nothing but great reviews about their systems.

 

Stick with SP. You will spend more replacing the filters with those cheap units.

 

what is the life generally of the spectra pure filters? I know there are a lot of variables but what would be the worst case to best case. I know spectra pure is a lot better brand that most and the color change resin seems really nice to

 

Update, I have bought the refurbished 90 GPD question the TDS meter (HM TDS-3) out of the box is it going to do what I want and what solution do I need to calibrate it?

 

All sediment and carbon block filters should be changed at least every 6 months regardless of the vendor or manufacturer. Their sole purpose is to protect the expensive RO membrane which is the workhorse of the system and what protects the DI resin. Each component has a job to do and everything downstream depends on how well it works.
Where the Spectrapure systems shine is their use or absolute or near absolute rated sediment filters which actually protect the billions of tiny pores in the carbon block so it in turn can do its job of removing chlorine and protecting the membrane. Then they specially treat their membranes with a proprietary treatment which is proven to improve their rejection rate which in turn makes the DI last longer. On top of that they custom blend all their own DI resins in house so you get the freshest possible resin specifically for reef use. It is a well through out system from start to finish.

I would replace the resin with non color changing once it is exhausted. Color changing resin actually contains small amounts of dye which contributes to TDS, besides not being completely accurate. It can turn all at once, never, top to bottom, bottom to top, in streaks and so on. Alway use your handheld TDS meter and never rely on inlines or color changing resins.

Use this for TDS meter calibration:
http://spectrapure.com/TEST-KITS-ME...ation-solution-available-as-342ppm-3oz-Bottle

 

Great advice and great to know to.. Thank you

 

There are things you can do to extend the 6 month replacement schedule provided you have good water quality and a low silt density, little to no particulates in other words.
The first is always use softened water if you have it available, membranes love soft water as it does much of the work for them so they last longer. Another is you can use pressure gauges before and after the sediment and carbon filters to monitor headloss due to fouled or plugged filters. If your waters suspended solids or particulates are low the sediment filter can very well last longer than 6 months so you watch for signs of headloss and change it when you start to see a differential between the upstream and downstream gauges. Along with that you need a low range chlorine test kit to monitor for chlorine breakthru from fouled or exhausted carbon. Yet another thing often overlooked is to do at least an annual disinfection of the system to keep things clean and sanitized. If you have ever seen a membrane covered in slime you would understand why it is necessary.

All these things can add up to a reduced cost of ownership and don't take much time or a large investment.