Reef Angel Forum

Hi everyone, sorry for the wall of a post, but I feel that detail is necessary in order to help others help me....


I have had a Precision Marine 4 Stage 150gpd RODI unit for about 4 years now. I always had low production numbers due to low water pressure and not having a booster pump(~70gpd). After moving into a new house I finally got a booster pump and expanded the RODI unit to 5 stage. With the booster pump I was producing maybe 90gpd, however I never worried about it since my post membrane TDS was 3-4.

I recently decided to replace my membrane after 4 years. I got the recommended 75 GPD Reverse Osmosis Membrane - Dow Filmtec 98% rejection rate from BRS....

Unfortunately, when I did the swap I threw away my old membrane right away and did not produce water till after garbage was already picked up.



Here is my problem.... Boosting 65psi I am producing ~130gpd with this 75 gpd membrane, thought this was awesome at first... but then I noticed I am also producing a very lousy 13-14 TDS post membrane.... Literally 25 gallons of product water used 70% of my DI resin.... I did a 2 hour flush on the membrane prior to sending any water through my DI resin.

My tap water TDS is on average 220-260... This means I should be in the ~4-5 TDS post membrane range with 98% rejection which is what I was previously getting with the 150gpd membrane with a lower rejection rate... But I am getting triple that 13-14....

BRS was amazing and even though I had my LFS order the pieces for me (trying to pass the money through a good LFS that is relatively new) they sent me a replacement RODI and flow restrictor without any confirmation that I actually purchased this from them. They just looked up my account and saw how much I have bought from them in the past and took my word for it... There is a reason when anything I need is on BRS I go through them...


After receiving the replacement membrane, swapping it out and flushing the membrane again for 2 hours before producing water... I received the same results... 13-14 TDS post membrane and ~130gpd... I spoke with them again and they recommended swapping out my membrane housing in case it had a hairline crack or it had swelled allowing water to bypass the membrane, I did this and I am still receiving the same 13-14 TDS post membrane...


I am completely at a loss at what is going on.. I do not get how a 150gpd with a 96% rejection rate was producing 3-4 TDS and now a higher rejection membrane is producing more water and a much higher TDS....


All my filters have been replaced.
My RO/DI stages are setup Like this and have been ran like this for about 2 years.

Stage 1 - 1 micron GE ROSAVE.Z DEPTH SEDIMENT FILTER
Booster pump - (I run sediment before in order to increase the life and efficiency of the pump, I do plan on buying a 6th stage to do a 5 micron pre-boost and move the 1 micron post boost)
Stage 2 - Refillable cartridge with Catalytic Activated Carbon for chloramines removal
Stage 3 - Pentek ChlorPlus Carbon Block
Stage 4 - 75gpd 98% rejection DowFilmtec Membrane
Automatic Shutoff Valve
Stage 5 - DI

Also, my automatic shut off valve is connected like this
Ports 1->2 (High pressure side) is my waste line.
Ports 3->(Screw side/Low pressure side) is my product water


Any ideas or help would be greatly appreciated...

I have the BRS 150GPD RODI system and I have always got about the same as you 13-14 post membrane.

No I was getting 3-4 post membrane with the 150gpd membrane... I switched to the 75gpd one which has a higher rejection rate and I am getting worse rejection and higher production makes no sense....

150gpd membrane 96% rejection - I got 3-4 TDS post membrane and ~70-80gpd production

75gpd membrane 98% rejection - I am now getting 13-14 TDS and ~130 gpd...



I used to make about 200 gallon of product water per DI cartridge... Now 25 gallons used up 70% of a new cartridge...



That is not right

What is your waste-to-permeate water ratio?

--Colin

That's what I'd check at this point, ^.

Same deal with mine, low TDS at the RO stage with the spectrapure 90 gallon setup. Changed out everything and got high TDS and burned up my resin. I need to test my waste to permeate ratio soon and fix that.

I had a very similar issue a few years ago. Turns out my membrane could fit in any way and I had it backwards. Swopped it around and TDS 0 after that. What got me thinking in that direction was also rapid depletion of my colour changing resin and very high flow rates.

Good thought. Mine will not fit backwards though. BRS loves me at $13 a packet for DI resin.

Membrane has definitely been installed in the right direction since day one. side with 2 little o-rings goes in first, side with large gasket style seal goes in last... Nipple is flush with teh top of the housing(without the cap being on), cannot push it in any further.

With having received 2 550 flow restrictors and having the issue with both I doubt its a faulty flow restrictor. 550ml/min = is approximately 209 gpd.


I produce 6 gallons/hour = 144gpd

144gpd product water to a max of 210 gpd waste water... 1:1.46 ratio Product:Waste.... That is waaaaay off and they agree... I have completely changed all my hoses for my waste line to ensure there is no clog.

I guess I could test producing water without any flow restrictor and see what happens.


They have gotten to the point where they want me to send in my RODI unit for testing lol....


I have checked the connections so many times that I know off the top of my head where each line goes.

Let us know what you find out. I think some of us are in about the same boat as you. I went from a 90 gpd membrane to a 75 and bought a new flow restrictor to compensate. Since then I am using lots of resin to get pure water.

Fat

I have a similar issue with my "98%" rejection rate membrane. I got mine from buckeye and I can't even get the same post membrane tds as my original maxcap 90gpd membrane that was 3 years old..

I have low incoming 20tds and this membrane will get 2 tds best case most of the time it's at 4 tds. It's crap.. Wish I never went with buckeye it's always an excuse and what hokey thing to try next vs just giving me another "tested" membrane.. Waste of money on my end should have stuck with spectrapure.. Fwiw my old standard membrane went from 0 tds to 1tds so I swapped in this revolutionary fully certified membrane to just burn up my resin. I also tossed my old membrane like a really smart guy.. At least brs is helping you though I'm going to go with a spectrapure membrane when my resin depletes but it's probably wiser and cheaper for me to do it now. I'm just bitter that buckeye isn't doing anything.

Tricks I was told that didn't work were to make sure the membrane is seated properly.. Use hot water on the rubber gasket to make it more pliable, run the unit to waste for 24hrs(im in California in a drought) and some others that didn't work. I'm not sold on these ultra high efficient membranes myself might just get the standard one again..

Man... I'm really wasting resin then... I get 13tds post membrane at best.

I'm surprised your having an issue with Buckeye. Russ is usually really good with this type of stuff, and from what I've seen customer service has been spot on. But I guess every experience is different.

I wish I knew what my post membrane TDS was.. I need to get one of those triple meters they have now. My post resin TDS is always 0-1 and my resin lasts almost a year. I also am pretty diligent in flushing the membrane before I make a batch of RO.

lnevo wrote:I'm surprised your having an issue with Buckeye. Russ is usually really good with this type of stuff, and from what I've seen customer service has been spot on. But I guess every experience is different.

I wish I knew what my post membrane TDS was.. I need to get one of those triple meters they have now. My post resin TDS is always 0-1 and my resin lasts almost a year. I also am pretty diligent in flushing the membrane before I make a batch of RO.

You don't need those triple meters. Just use your handheld. Detach the tube running from your RO to your DI from the fitting and drop that water in a cup and measure away! That's what I do. From what I've heard, those in-line meters aren't as accurate because of temp compensation.

Dont have a handheld...need one of those too.

I've got two dual in-lines... One from each measuring Post Membrane and one from each measuring post DI... Always good to have two different units giving you results... I also have a hand held. I use that to test my tap water from time to time. There is no point measuring TDS post Sediment/Carbon blocks as they actually remove more of the undissolved solids in water and break them down into easier particles for the membrane/di resin to clear out... Typically you will see the same TDS post sediment/carbon as you will from your tap... sometimes it might even be a little higher or lower...


At this point BRS says I need to send my RO unit into them for testing.... I told them it might just be easier for me to order spectrapure membrane and if that works I want a refund.


Roberto, put it this way, if you normally have 12 TDS post membrane, you will use up DI resin 3 times as fast as someone with 4 TDS post membrane... 6 times as fast as someone with 2 TDS post membrane... It's a huge difference...

This is so frustrating, I put all the numbers together, I have spent about 480 on RO/DI equipment from BRS... Maybe if they agree to fix it on their dime and ship it back on their dime I will consider absorbing the shipping cost of a RO unit to them...