How do you know which RO System filter to change?

[choff]

Ask Spectrapure. They have some washable filters that might recommend. The 0.2 micron ZetaZorb can be carefully rinsed though so you may not need anything else.

Thanks, I did email them as well this morning. I Was curious to see what you thought as well. :)

 

[AZDesertRat]

I am not a fan of multiple filters in front of the membrane, everything you add has an associated headloss. I use one 0.2 micron absolute pleated ZetaZorb and one 0.5 micron carbon block. The ZetaZorb can be carefully rinsed and with its 10x the surface area of a normal filter it stays cleaner longer and with less headloss even though it filters much better.

 

[choff]

I am not a fan of multiple filters in front of the membrane, everything you add has an associated headloss. I use one 0.2 micron absolute pleated ZetaZorb and one 0.5 micron carbon block. The ZetaZorb can be carefully rinsed and with its 10x the surface area of a normal filter it stays cleaner longer and with less headloss even though it filters much better.

Thanks, AZ. They got back to me quickly this morning. They said if iron is still present in the water I should work with my local water softener company who specialize in that. He said they might have to add a berm filter or oxidizer to our system. Iron won't be pulled from the system by mechanical means and will foul RO units. This is actually probably my issue with my current BRS unit and getting a spectra pure is probably not gong to solve it until I deal with the underlying issue.

My 2 issues with my current unit is my RO membranes fouling frequently and my DI resin dying very quickly even with the TDS going into the DI is always under 5 and most of the time reads 3. I always run the system for a few minutes before I let it hit the DI too, so there is no high TDS water hitting it on startup. This I can solve with better DI resin. The RO fouling seems to be a water issue I need to solve. I'm still gong to buy the specter pure, because I love the RODI bath when it shuts itself off.

 

[AZDesertRat]

The short DI life is probably CO2 in your water, it does not measure as TDS, is common in well waters and is a killer of DI resins. If you know the pH and alkalinity of your water you can use this nomograph to calculate your CO2 content:
http://spectrapure.com/frequently-asked-questions#calcc02

Or you can use a test kit such as this one:
http://spectrapure.com/TEST-KITS-METERS/CHEMICAL-TEST-KITS/Carbon-Dioxide-Test-Kit

 

[Saltine]

@AZDesertRat So I have my new Spectrapure Unit all setup. I flushed each filter individually, and currently getting 2 out of the membrane only 0 with DI. Pressure just under 60psi. How do I know when it's time to replace the sediment/carbon filters? When the pressure drops? or more TDS out of RO line? Lastly, I only make 5g with of water at a time, I checked the TDS of my RO line and after sitting it was around 50, after 10-15 seconds it was down to two. Should I always flush the RO line before running it through the DI to extend the DI life?

My line in is at 175TDS

Thanks!
Salt

 

[AZDesertRat]

The easy answer is you replace the sediment and carbon block every 6 months on a set schedule and disinfect the system at least annually during filter changes.
The long answer is you monitor the headloss through the filters with your inline pressure gauge and chlorine breakthru with a $5+/- low range chlorine test kit and maybe extend the life to 12-18 months is you don't mind spending a few minutes every couple weeks monitoring filter condition.

I would try and make more than 5G at a time but that's not bad, it's the short spurts that kill things and shorten membrane and DI life. As long as you are making that much and using the system every 10-14 days to keep it fresh you should be OK. You are seeing the results if TDS creep, when the system is off the TDS in the tap water migrates through the membrane to the treated side since it has been stripped of its TDS and is trying to get back to its natural "dirty" state. A DI bypass you open for 30 seconds or so on start up flushes this out until you close the valve and make DI water. It is manual though so you have to be there each time you make water, at least on start up. Don't confuse the DI bypass with a flush kit which is on the waste line and pretty much worthless in this case.

 

[Saltine]

Thank you!!!

 

[LakeCityReefs]

I'm not even sure what type of RO unit I have. There is some sort of a symbol on it but other than that all I know is that there are 4 canisters, a probe with a light that goes red if the cartridges need to be changed and it is fed with soft water. There is a 5 gallon holding tank under my sink and it also feeds the refrigerator drinking water. My questions are:
Do all units take the same size cartridges?
In which order do I put the cartridges in (what goes in canister 1,2,3,4)?

 

[AZDesertRat]

Photos of your system would help. Sounds like you have a drinking water RO system which is usually not the same filters or configuration as a reef quality RO/DI system. Not to say it could not be converted to a reef system but it will cost a bit more.