RO/DI performance

[m-six hundred]

I've been having allot of problems lately with the performance of my membrane on my RO/DI unit.

I would like to hear everyone specs and performance on their systems.

Please list your housing brand, filter brand, IN/OUT TDS, PSI and Good:Bad water Ratio.

-Bulk Reef Supply 75 GPH per day housing
-Spectrapure filters, set up as a max cap.
-IN 759 & OUT 24 (759-24)/759 is 96.83% Rejection
-78 PSI
-4:1 ratio

Below is the problem I am having.

I just purchased a Spectrapure 99% rejection membrane.

I'm only getting 96.83% Rejection. My 2 yr old BRS 75 GPD membrane was getting 97.62% rejection. basically 6 TDS lower than my brand new Spectrapure membrane. I have let the new membrane run for easily 12+ hours now and it has still not improved.

It's hard to justify buying a new membrane for weaker results.

Please post your specs and performance.

 

[Sinekal]

My performance has dropped significantly lately. I was sure my filters were done so I replaced them. The performance was the same with the new filters. I should have done this before, but I checked my incoming tds, and I'm over 800 right now. I think the really high tds may be reducing the reject rate. I am not an expert, but I'm experiencing a similar issue and this was the conclusion I came to.

 

[Sinekal]

I left out that I too am using the dowe membrane that brs sells, and during winter was getting a 98-99 rejection rate, now I'm at about 96-97

 

[bambam918]

I would ask the guys at spectrapure. They are really good with helping out. Sammykonga was having a similar issue and they helped him to get more rejection.

My TDS IN are around 700 and my rejection is 98. I have spectrapure max cap

 

[azjohnny]

I am at 98.5% with my 99% Spectrapure membrane in a Maxcap

PSI-100psi
4/1 ratio
In-652
Out-10

2 things that could be effecting your results is Temp and feed TDS which both get worse in the summer.

 

[reefstew]

Mark run it for another week & check it again. TDS runs a lot higher in the summer. I have a Spectrapure PSP 1000 & the first reading were high but after 300 gal the TDS on the out side was 4

 

[reefstew]

1 more thing the TDS was at 4 was after the RO & before the DI

 

[briankmarsh1980]

I would give it some more time then retest. I dont know if a brs model can handle it but in a spectrapure system getting the psi between 80 and 100 makes a big difference via booster of course.

 

[m-six hundred]

Spectrapure actually told me everything is tested and rated at 60 psi.

 

[briankmarsh1980]

You dont want to go less then 60 psi. Warmer water and a higher psi will make the unit run better

 

[Sammykonga]

BRS 4 stage value plus
Spectrapure prefilters
BRS membrane
TDS IN 831
TDS OUT 28
I believe it's a 4:1 ratio. Spectrapure had me change it to theirs and I believe that is what they gave me.

So about a 96.5%. With the new prefilters from spectrapure I sometimes will get closer to 97%.

Now, all that said, I'm going to replace the membrane soon with spectrapures 99%.

 

[m-six hundred]

RO/DI performance

Be careful I was in the same boat and I'm getting no better than brs membranes. I feel like I wasted $60.

 

[landy]

North Phoenix


Spectrapure filters

ultra high rejection 90gpd membrane
double sediment
double carbon
maxi cap DI

430ish in 4 out (RO)
85 psi

Best part, I last changed the RO membrane 9/30/09
IDK how this thing has lasted this long, even with the religious changing of the sediment and carbon filters.


I agree on giving it a week, run some gallons thru before you worry about the rejection ratio.

after that, if its still not right get with spectrapure they will hook you up.

landy

 

[petesreef]

have been dealing with the same problem..been burning through DI like crazy lately. My BRS 5 stage has been running at aound 30 TDS before DI. Changed all filters and also bought a new membrane from Marine Depot. TDS was around 35 after a week of running. Purchased another membrane from BRS and have the same results. Im thinking its the crap in the water during summer

 

[geemanaz]

Have you check the flow restrictor see if any build up or might be clog.
If remaber right that have to get the right size flow restrictor for membrane

 

[m-six hundred]

Yes I have, purchased a new restrictor with the membrane.

 

[jporter]

I am making some top off water now and my readings are:
Into RODI = 484TDS
After membrane = 6TDS
After DI = 0TDS
After Maxcap/Silicabuster = 0TDS

JP

 

[evolved]

It's a bit of a bastardized system, but the pre-filter housings are from a Watt's system (as well as the main "rack"), the membrane housing is a Spectrapure with a pressure gauge, and then there's a 2-stage Spectrapure DI add-on. Also running a booster pump, and there's a T and check value before DI stages with a 3g pressure bladder tank for RO drinking water.

All Spectrapure filters, a 90 GPD membrane, and the high capacity DI cartridges.

At this time of year for the membrane:
-IN ~900 & OUT ~25, so around 97% Rejection (but it'll do 98%+ in the winter/spring when the incoming TDS is down to 350 or so)
-90-95 PSI
-4:1 ratio

And of course both stages of DI are 0 out. I change them once their output is a steady 1.

 

[frogg21]

tds creep

tds creep

" ... and there's a T and check value before DI stages "

Does the check valve help with TDS creep?

http://www.copyright violation.com/content.php/182-RO-DI-TDS-Creep-is-it-worthy-of-concern

 

[m-six hundred]

He can probably bleed off the high TDS creep like I do. That way you do not push HI TDS through your MC and SB cartridges.