R O D I Unit Help!

[Aquatic Dreams]

OK ... Thanks for all the info. In reality though I've been drinking 132 ish TDS water for years and I've been unknowingly giving my reef tanks 109 ish TDS water for the last year. So if I'm drinking 8 TDS and giving the reef tanks 2 TDS it's going to be a giant step up.

 

[Dan Cole]

The TDS should be zero after the DI but yes a huge step forward...the only issue is how often you'll need to replace those DI cartridges.

Dan

 

[Aquatic Dreams]

Actually I just found out that the 1 lb of DI resin that I got doesn't fill the cartridge all the way. So it looks like the tanks are going to have to settle for the now 7 TDS until I can get more. LOL

So is this membrane rated too high in GPD or is it just the rejection rate that is the problem? Or both? Actually I just downloaded the user manual for this unit and I believe it is rated for 90 gpd. So next time I should get a membrane with a higher rejection rate closer to 98% and that's rated for 90 gpd or less correct?

 

[AdInfinitum]

BTW the more pressure you run will make the membrane more efficient regarding the good to waste ratio... if your restrictor is 90gpd and membrane is 100 not a huge deal...

All the tap water users that are running successful reefs on this forum would think you are doing great at 9tds...but it will rip through DI resin if you bother with DI at this point...

 

[Aquatic Dreams]

Also something else I'm not sure if I should be concerned about or not. Just to test I filled up two 32 oz deli containers. One with RO and one with waste water. When the waste water container was full the RO container was about 3/4 full. I was expecting the RO container to be about 1/4 to 1/3 full as I heard the ratio was 4:1 or 3:1. Does this indicate a problem?

 

[Aquatic Dreams]

BTW the more pressure you run will make the membrane more efficient regarding the good to waste ratio... if your restrictor is 90gpd and membrane is 100 not a huge deal...

All the tap water users that are running successful reefs on this forum would think you are doing great at 9tds...but it will rip through DI resin if you bother with DI at this point...

HA ... I was just typing mine as you replied. So does that explain my findings in regards to the ratio that I posted?

 

[AdInfinitum]

Yes, sounds like you have a leak somewhere which would account for the higher than expected tds. To get that close to 1:1 you would need to be running around 175psi through the membrane.

 

[Aquatic Dreams]

Yes, sounds like you have a leak somewhere which would account for the higher than expected tds. To get that close to 1:1 you would need to be running around 175psi through the membrane.

HMMMM ... A leak somewhere as in the RO membrane canister? Should I pull out the RO membrane and reseat it? I'm not using the 3rd DI canister. The unit goes form Sediment (Canister 1) to Carbon (Canister 2) and then to the RO Canister that sits on top of the unit. I see no leaking anywhere outside of the unit. Should I pull all the tubes and re-insert them perhaps? I'm unsure what exactly you mean by 'LEAK'.

 

[AdInfinitum]

Yes, the leak will be in the seating of the membrane. Yes some water is passing through without going though the membrane unless the membrane is faulty itself.

 

[Pipes]

If there is a "leak" it will probably be in the seat. Where the membrane bottoms out inside the membrane housing. If you pull it out, look at the center ring, and see if there is a hairline crack. This is caused by inserting the membrane to roughly. Been there, done it...

 

[Aquatic Dreams]

OK ... first off I want to thank all of you for all your help and suggestions and for answering my endless questions. It's a bit of a learning curve when you've never used an RO unit before and I'm glad there are many knowledgeable and experienced people here to walk me through it. But I've still got a few questions ... I'll get there eventually.

So I made several 5 gal. jugs of 7 TDS water last night. I took the membrane out and put it back in again ... twisted it around a bit to make sure it was in all the way but no difference in the ratio. This weekend I'll take it out and have a closer look for cracks etc. Should I be using a silicone lubricant or something around the rings and the seal? Also after a bit more research the membrane is supposed to have a 98% rejection rate ... the minimum is 90% whatever that exactly means. I was getting 6 TDS at one point which is about a 94.5% rejection rate from my calculations.

Now about the DI resin. I have it in the cartridge but as mentioned it's not quite full. Is it fine in the cartridge for now or do I need to put it in a ziplock bag and suck some of the air out? I'm thinking that if I can get the TDS down to 3 with the RO membrane (If I can figure out where the issue is with it) why even bother with the DI. Couldn't I just re-route the hoses and use the third canister for a GAC filter before the RO membrane or something?

 

[Pipes]

Keep the questions coming. That's the only way to learn, and gives us something to think through.

For seating the membrane just wet the O-rings. No lube. Lubricant can contaminate your product water, not such a big deal for drain water other than clogging the DLFC.

With GAC, let it soak in water overnight before you put it in the RO. Then if you have a flush kit, flush it past the membrane. There will be particulate flush through the filter into the membrane when first put in.

 

[Dan Cole]

Actually I just found out that the 1 lb of DI resin that I got doesn't fill the cartridge all the way. So it looks like the tanks are going to have to settle for the now 7 TDS until I can get more. LOL

So is this membrane rated too high in GPD or is it just the rejection rate that is the problem? Or both? Actually I just downloaded the user manual for this unit and I believe it is rated for 90 gpd. So next time I should get a membrane with a higher rejection rate closer to 98% and that's rated for 90 gpd or less correct?

The higher rejection rate the better...you might pay a bit more for the membrane but you'll quickly get your money back in purchasing fewer DI cartridges or refills. Your flow restrictor is likely rated for a 90 GPD membrane so that should be okay. Your biggest issue is the rejection rate on the membrane you purchased.

Dan

 

[Nonuser]

Hey I have a question, if you install a RO Unit and then the pressure going to the sink is weak, whats the deal?

 

[zoomster]

Do you have a shut off valve between the R.O. feed line from your plumbing and the inlet for the R.O. unit bud?

 

[Nonuser]

Do you have a shut off valve between the R.O. feed line from your plumbing and the inlet for the R.O. unit bud?

yes sir,

I live in an old apartment building and I have the water lines coming into the sink with the shut off valves. I then put in a nifty t fitting. with its own shut off going to the RO Unit. When I turn this badboy to by pass the unit, the water is like a slow stream. when I have the unit running the stream is about the same maybe slower. Wondering if the booster pump is what I need?

 

[zoomster]

Do you know how much water pressure you have now?
Most RO manufactures say they need a min of 40-50 PSI. But recommend about 60 - 80 PSI I believe for top-notch performance.
If you have less that 40 then I would personally say a booster pump is worth it.
Also, an honest Plumber would probably say
A min of 35 PSI for smaller units.

 

[Nonuser]

well sir,
That's what I was thinking. this old apartment isn't so great with water pressure and a booster pump as you suggest would probably do the trick. Thanks.

An Honest Plumber !?! that's like saying Jumbo Shrimp lol....

I'm kidding, I used to be an apprentice Electrician and all the trades used to give each other a hard time

 

[Skim]

I have tested a few membranes over the years and the best you can get is DOW FILMTEC. The big difference is their testing is done at 50 psi not 60 psi. The 75 Gal membrane is considered to be the standard that others try and copy. After over a year I am still getting 98% almost 99 % rejection, for almost 6 months I was getting 99% rejection, not bad for 98% rate membrane.

I took this from DOW's product information page.

FILMTEC home drinking water elements are rated a 50 psi and will purify about 20% more water than competitive elements rated at 60 psi (please see reference charts on page two for more information).

 

[zoomster]

well sir,
That's what I was thinking. this old apartment isn't so great with water pressure and a booster pump as you suggest would probably do the trick. Thanks.

An Honest Plumber !?! that's like saying Jumbo Shrimp lol....

I'm kidding, I used to be an apprentice Electrician and all the trades used to give each other a hard time

There are 1 or 2 honest ones left bud.
As a matter of fact, we have a very nice and generous member here who is one.
But I know what you mean. All trade guys have names for other trades.