LFS brand RO/DI

My tap water TDS is 535, my RO only TDS is less than 3 and my DI cartridges last about 9 months to a year with a 100G display/30G sump and a 16G nano reef aquariums. Randy Holmes Farley recently reported 10 years out of a single Spectrapure RO membrane following their recommended filter replacement and maintenance schedule, this is almost unheard of. I have 2+ years on my current Spectrapure membrane and the rejectionb rate is still 99.43% with RO only last I checked.
The 0.5 micron, Chlorine Guzzler style carbon block is the absolute best you can buy anywhere and will last up to 20,000 gallons of normally chlorinated water.

 

Noob question after all this...do you recommend an inline TDS or prefer a handheld version?

 

Handheld hands down. The inlines are like a litmus paper test, presence/absence but lack the accuracy of an equal priced handheld like the HM Digital TDS-3 or TDS-4TM. I actually prefer the upgraded HM COM-100 which is around $50-$60 but a much better meter testing down to the tenths of a PPM TDS.
Inlines are not truly temperature compensated and actually read air temperature not water temperature so can be off quite a bit since air temp and water temp are rarely the same.

The handheld is also much more versatile since it can be used to test tap water TDS, RO only, RO/DI, the ASO reservoir, the LFS, a vending machine, the neighbors, bottled water etc. The inline is dedicated to two places and cannot be used portable since they require flow past the probe.

 

Get in on a group buy, and grab this one with free shipping for $180

75 GPD RO/DI 5 Stage *PLUS* System - English

such a great product.

 

That is an OK deal but nothing special and here is why. It contains a relatively coarse 5 micron nominal rated sediment filter, an unneeded 5 micron carbon block, a dry untreated and untested RO membrane and standard off the shelf DI resin.

For $199 you can get a 0.5 micron absolute rated sediment filter, a 0.5 micron carbon block, a 90 GPD specially treated and batch tested high rejection rate RO membrane and SilicaBuster DI resin specifically blended and tested for reef quality RO/DI water.
Third one down the page here:
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You would need to add a TDS meter but handhelds are much better than inlines so you would probably need one with either system anyway.

Another good system is the Optima Automated here:
http://www.purelyh2o.com/index.php/...ypage=flypage.tpl&product_id=65&category_id=7
With it you get a 1 micron sediment filter and carbon block both which are much better suited for our needs.

 

Hey AZ do you really feel that flush kits are a waste of $10?? plz explain, Im getting rdy to buy the refurb spectrapure and was going to get the flush kit and the handheld tds meter after reading ^^^^ any thing else you recomend??

 

Get the TDS-3 TDS meter for $25 but pass on a flush kit, they don't do anything. Thats why Spectrapure doesn't offer them as standard equipment.

All a flush kit does is bypass the flow restrictor so you slightly increase the velocity of the tap water surrounding the membrane when you open the valve. It does nothing to eliminate TDS creep which is actually on the treated side of the membrane not the waste side. If you cut a membrane apart you would see its a thin film fabric wound around a core with a spacer material between the layers. The little bit of velocity you gain when you open the valve isn't enough to create a scouring effect on that much surface area. Plus in order to do any good it would have to be used EVERY time you shut the system off without fail from day one. Once TDS or dissolved solids sit in the membrane they begin to build up and solidify on the TFC fabric and no amount of flushing in the world will clean it off. Large municipal and industrial membranes get around this by doing chemical cleaning treatments periodically and flushing with massive volumes of water. Its very different.

For our uses just make sure you take the few minutes it takes to flush the filters and start the system up properly then measure the waste ratio and trim the restrictor to the recommended 4:1 waste ratio and thats all the flushing you will ever need. The 4:1 is what flushes the membrane and disposes of the brine or waste and keeps the membrane fresh, not a waste valve.
Some companies like Coralife are even so stupid they suggest backflushing the membrane by reversing the flow temporarily. If you think about it, what that does is put large amounts of untreated tap water on the good or treaed side of the RO membrane which is exactly what you don't want to do?