RO DI PPM value

[AZDesertRat]

Silica and silicates are handled by the DI resin which is last in line. If you are having particulates or sediment problems take a look at the 0.2 micron ZetaZorb found on sale here:
SpectraPure Customer Appreciation SALE! 20% - 50% off

I am told this is a very popular prefilter in the NYC area as they have very high sediment, particulate and colloidal material loadings and its about the only thing that works well for them. The filter is 0.2 microns absolute so removes 99.9% of everything 0.2 microns and larger plus is pleated so has 10x the sufrace area for long filter life and low pressure loss.
Most all TDS meters are factory calibrated with 342 solution but notice that solution has different values depending on the method you are using with the COM-100, make sure you are reading ppm NaCl as it is calibrated to that at the factory. Look at the bottom of the page here:
calibration solutions

drainbamage, yes 18-30 is way too high for RO only and out of sight for RO/DI. A good RO should take 400 down to no more than 6-8 and of course RO/DI should be 0 and nothing else. My tap water TDS exceeds 800 and my RO only averages about 5 so it is possible. Heck the Water & Ice store near me gets it down from 800 to only 13 with RO only and they make a couple thousand gallons a day.

 

[Ricordea]

Silica and silicates are handled by the DI resin which is last in line. If you are having particulates or sediment problems take a look at the 0.2 micron ZetaZorb found on sale here:
SpectraPure Customer Appreciation SALE! 20% - 50% off

I am told this is a very popular prefilter in the NYC area as they have very high sediment, particulate and colloidal material loadings and its about the only thing that works well for them. The filter is 0.2 microns absolute so removes 99.9% of everything 0.2 microns and larger plus is pleated so has 10x the sufrace area for long filter life and low pressure loss.
Most all TDS meters are factory calibrated with 342 solution but notice that solution has different values depending on the method you are using with the COM-100, make sure you are reading ppm NaCl as it is calibrated to that at the factory. Look at the bottom of the page here:
calibration solutions

drainbamage, yes 18-30 is way too high for RO only and out of sight for RO/DI. A good RO should take 400 down to no more than 6-8 and of course RO/DI should be 0 and nothing else. My tap water TDS exceeds 800 and my RO only averages about 5 so it is possible. Heck the Water & Ice store near me gets it down from 800 to only 13 with RO only and they make a couple thousand gallons a day.

As for the calibrations solutions order numberTS-C342.Just want to make sure I'm right here?Now if the 0.2 micron is being used.What prefilters ahead of this might be need?I can add 3 more if need be.Not sure on the micron size,being there are a few that are offered.Being sediment is in different sizes.Also if I had a total of 3 or 4 sediment filters.Do I need 2 pressure gauges,ahead/behind each chamber?So I can tell which sediment is starting to fail.
Thanks for that nice sale at Spectrapure.Now I just have to figure out the goods I need.

 

[AZDesertRat]

Adding multiple prefilters is counterproductive. Each filter has an associated pressure drop so reduces the pressure available to the RO membrane both reducing its GPD and it removal efficiency. A single ZetaZorb prefilter is probably all you need, anything else will compound the problem as it removes everything you need as far as particulates, sediment and silt and will outlast other filters on its own. If the problem is monumental then maybe something like the LoadMaxx might be called for but that is very rare.
PRE-FILTER ASSEMBLIES

My suggesting is to call Spectrapure directly or contact them through their forums on many of the popular reef keeping sites. Not sure if they have a forum here but they do on Nano Reef, Reef Central, 3Reef and others

 

[Ricordea]

Adding multiple prefilters is counterproductive. Each filter has an associated pressure drop so reduces the pressure available to the RO membrane both reducing its GPD and it removal efficiency. A single ZetaZorb prefilter is probably all you need, anything else will compound the problem as it removes everything you need as far as particulates, sediment and silt and will outlast other filters on its own. If the problem is monumental then maybe something like the LoadMaxx might be called for but that is very rare.
PRE-FILTER ASSEMBLIES

My suggesting is to call Spectrapure directly or contact them through their forums on many of the popular reef keeping sites. Not sure if they have a forum here but they do on Nano Reef, Reef Central, 3Reef and others

I just thought by adding some prefiters,to get possible longer life out of the 0.2 micron.Than just having the 0.2 being the only work horse.I see you mention reduction of GPH threw membrane.As it leaves the carbon,I have in place is a booster pump.The pressure going into the membrane is 90 PSI.

 

[AZDesertRat]

Since you have a boosted system you could place a single higher micron prefilter in front of the ZetaZorb. I would then plumb it so the booster falls between the high micron prefilter and the ZetaZorb so you reduce any chances of starving the suction side of the booster pump. I use a booster pump too and just changed my first ZetaZorb after 18 months of usage and only a 2 psi pressure drop since new, the filter still looked clean and white but It was time for a new carbon block so I did both at the same time. I do not recommend going that long but I was doing an experiment and was monitoring both the pressure drop and for chlorine breakthru on the carbon.

 

[R2E2]

Yeah Holy **** ha we are currently looking for higher grade D/I cartridges if that is even possible. We are currently using all Coralife Cartridges (D/I, Carbon, Sediment)

I don't know if you can get small quantities of these resins, but high capacity resins are available. DOWEX Monosphere 545C is a high capacity H+ cation resin (2.5 eq/l), and DOWEX 1 LC NG is a high capacity anion OH- resin (1.2 eq/l). Ideally, you would want to run cation, then anion, then mixed (50% by volume of each).
Like I said though, I don't know if any distributors sell it in any small quantities. We order truckloads at a time at my work.

 

[melev]

like 5-10 ppm change your filters. Talk about wasting money ha, in our store we have a aquafx great white r/o system (7stage (We added a extra sediment before the water hits the unit)) we change our sediment and carbon every 12-15 days. We are making about 300 gallons a day. The D/Is can get expensive for us to change too since there are 3 of them and it only lasts a week. The membranes only last about 2 months for us. :tire::tire: It's a big pain in the butt.

Something sounds off about this. I'd like to get more specifics from your setup to help you determine what's going on.

I can tell you this: Change out the sediment filter weekly. That is your cheapest filter and it is visual proof that it is extracting crud from the water.

Are the membranes running in series or side by side?

What is the TDS coming out of the membrane(s) prior to the DI?

Are the DI cartridges running in series?

Does this system use a booster or permeate pump?

Do you ever turn it off or does it run around the clock?