Need help picking out a ro/di unit

[davidwinn101]

Have used the BRS 4 stage for years and love it.

 

[AZDesertRat]

Use the correct micron range filters and you will like it even more.
Carbon is made up of billions of tiny microscopic pores so needs protecting to adsorb chlorine and other organic chemicals. When you consider you can see 40 microns with the unaided human eye, 5 microns is actually pretty coarse, about as effective as a screen door. Use something more like 1 microns or ever 0.5 or 0.2 microns absolute and your carbon will work better, last longer and protect the RO membrane better so it lasts longer and works better which is its sole purpose.

I love BRS chemicals but they have work to do on their RO/DI line.

 

[prsnlty]

I owned a Typhoon III and sold it for a Spectrapure MaxCap. No comparison at all, light night and day difference. DI went from 150 gallons up to 830 measured gallons on the very first cartridge.

That's interesting. I've noticed that my di has been used up faster than it used to be and the first filter looked bad super fast than previous replacents that I purchased a year ago from elsewhere. I usually buy 4 at a time and change them every 3 months whether it's needed or not. This time I bought the BRS replacements. I always buy their di though. My Ro unit is a Kent 4 stage.

 

[AZDesertRat]

Check out Spectrapures near absolute rated 1 micron sediment filter and 0.5 micron 20,000 gallon carbon block to protect the RO membrane and their SilicaBuster DI resin for a reef specific blend that should last several times longer than anything you have ever used before. BRS doesn't blend their own, its right off the shelf like most others.

If you really want long sediment filter life check out Spectrapure's 0.2 micron absolte ZetaZorb. Not only is it hundreds of times more effective it has lower headloss and lasts much longer due to its 10x more surface area. It can also be carefully rinsed and reused several times before replacing.

What is your RO rejection rate? For every 2% it drops below the minimum recomended 98% you cut your DI life in half.

 

[prsnlty]

For every 4 cups rejection I get 1 cup rodi. I'm not exactly sure how to measure it otherwise. I have a 100gpd unit.

Jackie

 

[prsnlty]

Check out Spectrapures near absolute rated 1 micron sediment filter and 0.5 micron 20,000 gallon carbon block to protect the RO membrane and their SilicaBuster DI resin for a reef specific blend that should last several times longer than anything you have ever used before. BRS doesn't blend their own, its right off the shelf like most others.

If you really want long sediment filter life check out Spectrapure's 0.2 micron absolte ZetaZorb. Not only is it hundreds of times more effective it has lower headloss and lasts much longer due to its 10x more surface area. It can also be carefully rinsed and reused several times before replacing.

Good to know, thanks! I will check this out and order for my next change

Jackie

 

[AZDesertRat]

That is your waste ratio, often confused with the rejection rate but very different.

The rejection rate is the removal efficiency of the RO membrane. To calculate your rejection rate you need to know your tap water TDS and your RO only TDS before the DI if you have an RO/DI. Take the tap TDS, subtract the RO TDS then divide that number by the tap TDS and multiply the result by 100.

Using my TDS numbers of 560 tap and 2 RO only it goes as follows. 560-2=558, 558/560=.996, .996x100= 99.6% rejection rate or removal efficiency. I suspect if you have a 100 GPD Dow Filmtec membrane which I really hope is not the case it will be considerably worse than that since the Dow 100 is not really a RO membrane but is a step below in efficiency called a Nano Filter or NF not RO. A NF filter is only 90% rejection rate when new and was never intended for drinking water, it is rated "Pool and Spa Use" by the ANSI/NSF where the 75 GPD is rated for drinking water use and 96-98% rejection rate. Any RO vendor with a little experience will do everything in their power to talk you out of the 100 GPD since it cuts your DI life to about 1/8 to 1/16 what it would be with the 75 GPD RO membrane.

If you have the GE Water 100 GPD it is more similar to the 75GPD Dow Filmtec is all respects, flow of 75 GPD included.

 

[Kworker]

+1 on BRS unit, Make sure you get the float valve for it. its only 12 bucks and the system already comes with the automatic shutoff valve. So for 12 bucks you will never have to worry about flooding and turning on/off the unit.

 

[AZDesertRat]

Kworker, if you are in NY make sure to use better filters than the BRS systems come with. While NY has very low TDS or dissolved solids thye have some of the highest TSS or suspended solids in the country and are scrambling to fix that due to EPA fines. It is the suspended solids that plug or foul filters and render them useless. This is specifically the reason Spectrapure tested their ZetaZorb at many end users homes and LFS in the NY area since they were noticing so many complaints of short filter life and high headloss numbers, lowering the RO efficiency and shortening DI life. Monitor your incoming pressure before the sediment filter and your RO pressure closely as a drop in pressure makes a huge difference in RO efficiency and a fouled carbon block will ruin a membrane very quickly due to chlorine breakthru.

 

[prsnlty]

Ok. My tap before ro is 201 (we have a whole house salt softner system) after is 2. 201/199= 1.01x100=101, yes? I have to check and see which membrane I have.

Jackie

 

[AZDesertRat]

It should be 199/201 so the rejection rate is 99% not 101% which isn't possible.
If your RO only TDS before DI is really 2 then you are doing very good. You did check the RO water only and not the final RO/DI?

The only other thing that eats DI quickly is CO2 in your water and it passes through the membrane so the only way to remove it is with a degassing tower which is simple to build. What is your final RO/DI TDS, is your DI a full size 20 oz vertical and how long is DI lasting you? Are you using bulk resin and if so is it being stored properly since it only lasts about 6 months even when stored vacuum sealed and unopened in the refrigerator. Are you packing it tightly so there are no voids or space for water to channel or short circuit?

And by the way, you are doing the best thing you can do for your RO by using softened water, they love soft water since it does much of the hard work for them.

 

[prsnlty]

It should be 199/201 so the rejection rate is 99% not 101% which isn't possible.
If your RO only TDS before DI is really 2 then you are doing very good. You did check the RO water only and not the final RO/DI?

The only other thing that eats DI quickly is CO2 in your water and it passes through the membrane so the only way to remove it is with a degassing tower which is simple to build. What is your final RO/DI TDS, is your DI a full size 20 oz vertical and how long is DI lasting you? Are you using bulk resin and if so is it being stored properly since it only lasts about 6 months even when stored vacuum sealed and unopened in the refrigerator. Are you packing it tightly so there are no voids or space for water to channel or short circuit?

And by the way, you are doing the best thing you can do for your RO by using softened water, they love soft water since it does much of the hard work for them.

The membrane is from purewaterclub.com 100gpd

It should be 199/201 so the rejection rate is 99% not 101% which isn't possible.
If your RO only TDS before DI is really 2 then you are doing very good. You did check the RO water only and not the final RO/DI?

Yes, I had it backwards. It is really 2. And it was before di. After di it reads 0 atm. New brs resin was added 1 week ago.

Yes they are the 20 canisters. As far as how long di lasts... I have 3 sw tanks. 125g, 45g corner and 27g hex. Plus a 10g qt. I change about 30g per week between them all. Di lasts approximately 3 months if I don't mess up and forget to keep up with the hh softner system.

I still want to check out the spectrapure do to worry about silicates. I don't have a test for it but just to be safe.

My water before the system is horrible! Somewhere in the 700s. Super high in iron and sulfer. Our HHS has an iron tank and a uv on it, it is that bad... I'd rather go through a whole lot of salt and use the house setup than the well water.

Jackie

 

[prsnlty]

I didn't know there was a shelf life for sealed di no less refrigerate it. I only buy single use pkgs though . Non color changing. I think the color changing goes bad faster.

I will refrigerate from now on

Jackie

 

[Zeko]

Well this thread is definatly teaching me that rodi units are going to be a headache and a chore cant wait to get one and be with u guys in the info but now I'm on the fence again for what unit to buy lol

 

[prsnlty]

Lol, always learning

Jackie

 

[AZDesertRat]

Test your tap water from one of the outside hose bibs where it should be non softened water. Softeners don't remove TDS normally except in the case of the special iron reduction salts. Usually softened water has a higher TDS than the tap water due to the fact the ion exchange between calcium and magnesium for sodium or potassium is not a straight 1:1 ratio. If you have a few ppm Iron it will drop some of that but not drastically such as the 700 down to 200 you mention.

TDS or dissolved solids are in the 0.0001 micron range and pass through whole house filters and softeners other than the ion exchange which replaces the calcium and magnesium (plus a little iron in your case) with sodium or potassium. This i also why RO sediment and carbon block filters have very little to absolutely nothing to do with TDS, they remove the big floaty stuff in the 1 micron or whatever and larger size. It takes the RO membrane to remove 90-98+/-% of it and the DI to catch the remaining 2-10%. By protecting your membrane better it has an easier job and makes your DI last longer.

3 months at 30 gallons a week is not bad realy, thats somewhere around 500 gallons but it could be a little better. My DI lasts over a year and I have a 100G and a 16G reef and go through a lot of water in evaporation alone.

 

[AZDesertRat]

There is no comparison to Spectrapure for RO/DI. They are the only vendor to specially treat and test all their RO membranes to increase their performance, to custom blend all their own DI resins base on tens of thousands of hours of testing and one of the few to use low micron near absolute sediment filters and the much better capillary tube flow restrictors. 30 years of research and development really pays off.

http://www.reefcentral.com/forums/showthread.php?t=2173771

http://www.reefcentral.com/forums/showthread.php?t=2342795

 

[Eienna]

Well this thread is definatly teaching me that rodi units are going to be a headache and a chore cant wait to get one and be with u guys in the info but now I'm on the fence again for what unit to buy lol

It sounds to me like the Spectrapure is the way to go - or at least, that perhaps the filters on a different unit you buy could be switched out.

From what AZ is saying, I would bet that the spectrapure stuff will cost you less in the long run than these others. I myself will be looking into replacing my stock filters with that.

Don't bother with the purewaterclub unit. It's junk. I've had it before and you don't want it.

The whole thing seems complicated at first, but it gets easier

 

[prsnlty]

+1. I have a kent unit and it's a good unit but the media will get changed to spectrapure. Rodi is a necessity with any saltwater setup. You won't regret it.

 

[rhino56]

The BRS units use too coarse of sediment filters to protect the downstream filters and membrane so they do not last as long or work as well. The result is more frequent replacements driving the cost of ownership up. Also pass on the inline type TDS meters, they lack the accuracy of a good handheld which costs the same but are much more versatile. To check a RO/DI you need 3 TDS readings and the inline only gives you two so you cannot calculate your rejection rate.

I have the BRS 5 stage unit and I have switched out the sediment filter from the 5 micron that comes with it to the 1 micron (.06) and I change that filter every time I change the DI resin, which is about every six months or when my water reads 1 TDS. I change the carbon filters (the first one also switched out) every year and the RO filter every two years. There is a lot less rejection this way and I get water three times quicker than original.

I have a degree in Marine Biology (water), but if I needed advice I would ask Desert Rat. He is right about the BRS unit not being set up perfectly.

THIS^^^^

just get the BRS and order finer sediment filters.