RODI with High Rust Content Water

[cdness]

Currently I am burning a DI cartridge after about 30 gallons of water (or less). We have very rusty water in West Fargo due to the well that supplies the city. Sediment filters are shot after 20 gallons or so.

Do you think a whole house filter running prior to my RODI will have any effect on the filter life in the RODI system?

Is there anything else I can do to try reduce the amount of rust in the water, other than install a softener (it's a rental).

 

[-Logzor]

Did a quick search on the internet on the subject. I'm no expert but this seems to be recommending a hydrogen peroxide system, not sure what that system is exactly but here is the article : How to remove rust or iron, sulfur (sulphur) and manganese from the water | Ask The Water Doctor

 

[cdness]

Ouch, those aren't cheap at all. I wouldn't want to be adding that to the rental anyway...

 

[AZDesertRat]

First off, if you are eating DI filters that is an indication your RO membrane is not doing its job.
What are your tap water, RO only and RO/DI TDS readings? What is your water pressure and water temperature? What is your exact waste ratio as measured with a measuring cup or graduated container and a watch or clock?

Do you have a water softener and are you using softened water to feed the RO/DI system? Are you using a Rust remover salt such as Mortons Pellets?
Morton® Rust Remover Pellets

What is the pH of your tap water and do you have any idea if it contains entrained CO2? Your local water utility may be able to better answer this question for you but if its well water this may be one of your problems.

Spectrapure manufacturers a backwashable prefilter kit that may help your situation:
PRE-FILTER ASSEMBLIES

 

[cdness]

My pre-RO is around 400-600TDS, after RO is usually around 4 or 5 TDS. Temp I am unsure as it is off the cold water feed of the washing machine and I have not tested the exact waste ratio either.

No water softener on the system (its a rental)

I like the idea of the backwashable sediment filter. I am going to have to get one of those soon.

 

[AZDesertRat]

Your tap TDS is similar to mine at 630-800. My RO only TDS runs 2 to 3 but even at 4-5 you are doing very good as far as rejection rate at around 99%. I will bet money you have CO2 in the water and that is eating your DI resin. What are you using for resin, where do you get it and how fresh is it? Do you buy in bulk and how do you store it?

Resin, even when properly stored vacuum sealed damp in a "seal a meal" type bag has a shelf life of about 6 months if kept in the back of the refrigerator and out of direct lighting. It starts to lose its cationic and anionic electrical properties and is not nearly as effective when not stored properly. Some resins last longer and work better than others and some are blended for specific conditions. Look towards the bottom of the page here:
DI REPLACEMENT

You might give the folks at Spectrapure a call or email and describe your situation, they love a challenge!

 

[cdness]

I am using the BRS Color Changing resin in bulk. It has been stored out of light in the original mylar bag it came in, but not refrigerated (I didn't know it needed to be).

It is about 8 - 9 months old which could be leading to the issue too.

 

[Alicia83]

Following along...Live in the same area and looking to get a RODI system would like to see if you get this resolved, keep me updated

 

[AZDesertRat]

If its that old and has not been kept wet and vacuum resealed then kept in the fig then its not much use.
Never buy more than you can use in 6 months time, I try to stick with 3 months myself, add a little DI water if its not moist then re seal it and stick it in the back of the frig. You might try a SilicaBuster cartridge at $18 and see how it works for you, I think you will be extremely happy.
Untitled Document

 

[cdness]

Wow at those prices I won't bother with the refills at BRS. SilicaBuster it is.

Is it worth the money to add the MaxCap DI ahead of the SilicaBuster or should I just get a couple SilicaBuster cartridges?

 

[AZDesertRat]

I use the MaxCap and SilicaBuster combination myself.
As I mentioned, my tap water TDS averages around 630 recently but gets as high as 800 during periods when they change the water source blend. Our choices are all bad since its the Colorado River (ever wonder where all those minerals that came out of the Grand Canyon went???) and the Salt River (Three guesses as to hwo it gots its name and the first two don't count!).

My RO gets it to between 2 and 3 using a COM-100 TDS meter which is very accurate. Form there it goes to the MaxCap cartridge which lasts me a little over 1000 gallons before I start to see a 1-2 TDS reading which is when I change it out. I go through three MaxCap cartridges before I start to see a TDS reading from the SilicaBuster DI cartridge which is over 3000 gallons at which point I change the SilicaBuster cartridge. I just changed my third MaxCap and very first SilicaBuster DI cartridge in Mid October, it was just like 3 days short of two years since I installed the MaxCap UHE system in my house so in two years I went through the original MaxCap cartridge, two replacements and the original SilicaBuster. Thats $21 x2 for the MaxCaps and $18x1 for the SilicaBuster or a total of $60 for two years of RO/DI water at 0 TDS. Thats $2.50 a month which is darn cheap!

It looks like they have the MaxCap D-1 add on kit for $55 in the flyer which includes a dual inline TDS meter, canister, MaxCap cartridge and all the fittings you need to add it to your existing system. You would plumb it after your existing DI them install the MaxCap cartridge in your existing canister and place a SilicaBuster cartridge in the add on kit. The dual inline TDS meter tests the water after the MaxCap with the IN probe and after the SilicaBuster with the OUT probe so you knowwhen to change each. At $55 thats a steal.

 

[Buckeye Field Supply]

If your water quality is as bad as you describe ("sediment filter is shot after 20 gallons") you're not going to have much luck running an RO or RODI system. You need to trat your feedwater before it gets to the RO.

Because this is a rental unit, my guess is that you wouldn't be interested in the investment needed to pretreat the water...

Russ

 

[Devonjevon]

Would be interested in the pressure in your house. I to ran threw di until I purchased a booster pump.

 

[cdness]

So I discussed with the owner of the unit and they are willing to install a water softener. They were talking about the space saving water boss models. Anyone ever use those?

 

[cdness]

It looks like this may be the best bet for the money:

WaterBoss 900 Water Softener at Menards

What do you think? Will this help at all?

 

[AZDesertRat]

I would have the owner look at Sears also. They always have softeners on sale and I picked mine up quite reasonable and installed it myself.

 

[cdness]

Just ordered the MaxCap D2 upgrade. I figured the cost of the cartridge allows me to just add the full upgrade kit. My DI is separate anyway.

 

[cdness]

I just received and installed my MaxCap DI system. I replaced the single stage DI from BRS with the MaxCap. It was a cinch to install and came with everything needed. I didn't even need to buy any hoses. The issue with my DI I believe was old resin. This resin has not changed at all and looks like it will last a long time. The instructions for rinsing the DI were clear and well worth holding on to.

The only issue I have with the system sent is the bracket. The BRS one has a nice metal stronger bracket, but the MaxCap system came with a plastic bracket which will more than likely break in the future and need to be replaced.

AZ, Thanks for all the recommendations with the Spectrapure products. I have a few more BRS filters to use up, but when they are gone I'll be switching over to the better filters from Spectrapure. I may also add the back-flushable sediment filter as well.

 

[AZDesertRat]

I have been using MaxCaps for about 9 years and have never broken a bracket so they are pretty strong.
Personally I would not use the coarse BRS sediment filters since they are not very efficient. You are sending particles canc colloidal materials 5 microns in size to a carbon block that is like 0.5 or 0.6 microns in size so fouling the carbons pores rendering it useless. I always use a sediment filter at least the same micron size as my carbon block if not smaller so it has a fighting chance at survival. The reason many vendors use two carbon blocks is they are counting on the first one to be a sacrificial filter to protect the second one which makes no sense, a good low micron absolute rated sediment filter will do the same thing, cheaper and more efficiently with less head loss to the membrane. I would use a 0.5 or 0.2 micron absolute rated sediment filter and a single 0.5 micron carbon block for best performance and membrane life, after all, thats their only purpose, to protect the RO membrane.

Did you know you can see something 40 microns in size with the unaided human eye? That means 5 microns really isn't all that small, kind of like a screen door, and passes a lot of stuff through. A membrane filters down to 0.0001 microns so you want to keep as much of the big stuff out as possible so it stays clean and works as intended.

 

[cdness]

OK, thanks for the tips. I'll be making an order from Spectrapure for the main sediment filter. Maybe I can use the BRS ones as a pre-sediment, sediment filter until they are gone. Either that or I'll just sell them.