I have a typhoon III rodi system, and it's time for new filters, ro membrane should still be good. I don't think the typhoon replacement pack has the best filters, can you recommend a filter replacement set for this unit? Thanks
I believe AWI offers an alternate filter set with lower micron rated filters which is a better choice.
Personally I prefer Spectrapure filters and here is why.
The Spectrapure prefilters are absolute rated versus nominal rated meaning they filter out 99.9% of all the particulates down to and including the micron rating. Nominal rated prefilters can trap as little as 60% of the rated particle size. A better prefilter means it protects the carbon blocks billions of tiny microscopic pores better so the carbon can do its job of adsorbing chlorine not act as a secondary prefilter. I use a 0.2 micron absolute rated pleated prefilter with 10x the surface area of a normal spun poly filter. Not only does it filter better, it lasts longer and has a lower pressure drop due to the amount of area.
The better prefilter allows you to use a single high quality carbon block such as the KX+1 Chlorine Guzzler in the 0.5 or 0.6 micron size. The only reason vendors use two carbons the reason above, the first one is a sacrificial filter protecting the second one. Years ago carbon technology was not what it is today and they lasted as little as 300 gallons each before exhaustion so it took two to do the job. Todays 0.5 and 0.6 micron carbons last up to 20,000 gallons of normally chlorinated or chloraminated tap water. Notice I said chloraminated as these are excellent for chloramines too. Chloramines are hard on DI resins not really on a good carbon block, the carbon adsorbs the chlorine portion, its the ammonia that is tough and where the DI resin comes into play. I use a single 0.5 micron carbon block.
DI resins come in many blends and grades. Some good and some not so good. I used to own a Typhoon III and no matter what resin I used or how fresh it was it lasted 150 gallons before it started to show TDS on a handheld TDS meter. I switched to the MaxCap and SilicaBuster DI resins and my DI life is now over 1000 gallons per cartridge, huge difference. Spectrapure blends all their resins in house based on thousands of hours of bench, beta and lab testing. They have packed columns of resin hooked to tanks of TDS spiked water to test the resins and log all that data. Others use prepackaged resins straight from the manufacturer.
By going with a single carbon block you will have an empty 10" canister which can easily be converted to a second DI filter with about $10-$15 in parts and a few minutes time. Replumb it so its after the existing DI and add a refillable cartridge and you now have dual DI which gives you some bang for your buck. You can run the same resin in both cartridges and monitor the TDS from each, when you first start seeing TDS from the first one, move the second DI to the first position and add a new refill to the second so you get maximum life. Another option is do as I am doing and place a MaxCap DI in the first position and a SilicaBuster in the second. Again monitor the TDS from each but you will find the MaxCap extends the life of the SilicaBuster 3 or 4 times before it needs changing out.
At a minimum go with a 1 micron prefilter, 1 micron carbon block, 0.5 micron carbon block and a SilicaBuster DI cartridge or refill. The next step up would be a 0.5 micron prefilter, 0.5 micron carbon block and a MaxCap and a SilicaBuster DI. My ultimate would be the 0.2 micron pleated prefilter to replace the 0.5 above.
Coming from a surface water treatment plant background myself I was used to the graduated micron ranges like the Typhoon comes with and it took me awhile to grasp the advantages of the smaller micron sizes. In the plant we had rough screens, then sedimentation and finally filtration with fine sand and carbon kind of like the 10, 5, 1 micron arrangement. The difference though is as i explained before, the large micron size allows particulates and colloidal materials to plug or foul the downstream filters causing a loss of pressure and loss of chlorine adsorption capability. By protecting the carbon you do a better job of protecting the expensive RO membrane making it last longer and function better for a lower long term cost of ownership.