RO/DI--people who have it can you help me?

[sharuq1]

Ok so I have my new aquasafe unit setup and it has been up for about a month or so. At first my readings for TDS were 0, but lately they have been slowly climbing. My last reading was at 006ppm. Is this normal? I mean it hasn't been long, I expected the unit to perform optimally for longer than one single month. I have been using about 5-10g per week. Is there something I don't know, or do filters or DI really need to be changed every month??

[littlesilvermax]

Is the 6 ppm before or after DI?

[Delphinus]

Are you backflushing the membrane periodically?

It depends on your source water how long your prefilters will last. I find I get a few months out of mine, my source water TDS is around 180-200 I think. 6 is not an uncommon reading for the RO output, but I find in my case usually what happens is it's more of an initial surge right after turning it on, it settles down to zero after 30-60 seconds.

DI output is always zero though unless it's spent. Ie., if you're getting 6 after your DI then it's time to change the DI. You should be getting way more than a month out of your DI. I don't have an Aquasafe unit but I get at least 6 months out of my DI cartridges (to give you an idea of what is reasonable to expect).

One note, is your unit directly plumbed to a float valve on your sump? Because if it is, this is very hard on a RO membrane. The constant on/off cycles is very hard on the membrane. I found this out when I had to replace mine 3 times in a year. It's better to have a reservoir that feeds the float valve on-demand as per evaporation, and fill the reservoir in a single go when it gets empty.

[Myka]

What is the TDS of your tap water? What psi is the unit running at?

[digital-audiophile]

I've found similar on my unit that I just set up a couple weeks back. I am getting TDS of 2-4 with brand new media.

[Delphinus]

Between the RO and DI or after the DI?

[sharuq1]

The tap TDS is about 225 or so I think. The 6ppm is what is coming out of the unit, after the DI and polishing filter thing. Should I take the "polishing filter" off the unit? It is on after the DI, then the DI goes to the storage container dealie. (not sump, this is the container aquasafe sends with their maximus unit for home use).

I haven't checked psi (I don't know how, especially without spraying the house down with water i see no where I can put a psi measurer thingie) , but I really don't think the psi is the problem as I was getting 0 reading before and I am in the city not the country.

I don't know how to backflush the membrane.... :redface: If backflushing means turning the wastewater as high as it can go for a few mins then yes I have done that, but it didn't help.

The unit is plumbed into a tap and is turned on or off using the valve that is on the input line. It is not hooked up to a sump or anything like that. The DI does look like it is almost exhausted, but I just don't know why. Should I be turning the wastewater so high that it is a flow and the RO coming out is a mere occasional drip??

It looks just like this unit:
http://www.aquasafecanada.com/MAXIMUS%20II.jpg
http://www.aquasafecanada.com/MAXIMUS%20II%20TOP%20VIEW.JPG

[Myka]

Check the tds of the the water that comes out of the RO, but BEFORE the DI. You'll have to take it apart to do that. Just disconnect the line between the RO and the DI, and collect that water to test it. How many gpd is your RO?

[sharuq1]

TDS there is 18. The unit is supposed to be 100gpd. Also TDS before "polishing" filter (after DI) is same as what is coming out when polishing filter is hooked up, so guess it isn't that.

[littlesilvermax]

TDS there is 18. The unit is supposed to be 100gpd. Also TDS before "polishing" filter (after DI) is same as what is coming out when polishing filter is hooked up, so guess it isn't that.

If your post RO tds is 18 ppm, then you have one of three things:

1) very high tds water (like 600 or so) and it exhausts your DI quickly
2) a bad membrane (FWIW the 75 gpd, I like the Filmtec, seem to consistently outperform the 100 gpd ones)
3) very low pressure to the unit

How to solve the problems:

1) just have to live with it (BTW someone around here has awesome deals on DI resin)
2) get a new mambrane, and by the sounds of how much you are using stick with the 75 gpd ones
3) get a booster pump

FWIW even if your pressure is good, a booster pump wil up efficiency, that is why I bought one.

[Myka]

The membranes have different efficiency rates.

Filmtec 50 gpd = 98% rejection rate
Filmtec 75 gpd = 98%
Filmtec 100 gpd = 90%
BFS 150 gpd = 98%

If your tap water is 225 ppm, and you're getting 18 ppm out of the RO, then your efficiency is about 92%. If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. This way you should get about 4-5 ppm out of the RO, and your DI resin will last much, much longer. This is probably your cheapest solution.

[mark]

I'm running single digit TDS, not zero, but don't think it's the end of the world (this is considering the cups of salt mix I add, the Dow Flake, the Mag Flake and some people do keep reefs with tapwater).

[digital-audiophile]

Between the RO and DI or after the DI?

I'm getting the readings after the RO and DI.

[banditpowdercoat]

My source is 500-700PPM, and I routinely get 10-11PPM after DI

[sharuq1]

If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. Flow restrictor? What exactly is that? Is it the valve on the input or the metal valve on the output? Or is it something else? Are you saying I will need a whole new RO membrane?

[sharuq1]

Also, how do I flush the membrane? Do I turn the wastewater so none comes out of it or do I turn it so it's as high as it can go?

This is really disappointing...I can't afford to buy a new membrane, nor a booster thing.... I do have some DI here...should I just suck it up and change the DI a gazillion times? :sad:

How high can TDS safely go before I have to change things? 10? And if I have TDS should I be using Prime in my water?

[mark]

Aqua-safe instructions (http://www.aquasafecanada.com/Install%20Instructions.htm), section 7.1 talks about the flushing valve and the handle position.

[midgetwaiter]

The membranes have different efficiency rates.

Filmtec 50 gpd = 98% rejection rate
Filmtec 75 gpd = 98%
Filmtec 100 gpd = 90%
BFS 150 gpd = 98%

If your tap water is 225 ppm, and you're getting 18 ppm out of the RO, then your efficiency is about 92%. If I were you, I would change out your flow restrictor for a 75 gpd, and get a 75 gph membrane that is 98% efficient. This way you should get about 4-5 ppm out of the RO, and your DI resin will last much, much longer. This is probably your cheapest solution.

Myka is absolutely correct. Your unit is working correctly but because of the lower rejection rate of the membrane you are using up DI resin very quickly. This is why the Aquasafe units are cheaper but also not very effective with Alberta water.

The flow restrictor on the Aquasafe isn't a capillary type like used in most systems, it's built into the flush valve so if you do decide to get a new membrane you will also have to replace the restrictor, it costs only a couple dollars.

You will have to decide when you want to swap your DI, it's not a clear cut choice. 6ppm probably isn't a big deal but it depends what that 6ppm is. Test the water for phosphate at least and if you start to see that come through then it's time to replace the DI. Spring is here so you can expect to see some more phosphate then usual.

[Slick Fork]

I think you will defineatly have to buy a booster pump, those aquasafe units seem to be real fussy about pressure. DO NOT buy one from one of these outfits in red deer. check out www.purelyh20.com the booster pump will run you about $100 (as opposed to $300 here in red deer), a new membrane in the 75 gpd flavour will cost you about $30-$40 with the flow restrictor and flush kit (highly recommended). Make sure you insist on USPS for shipping otherwise UPS will whap you with a big brokerage fee. If you need DI, littlesilvermax is the guy to grab it from!!

Also, if your turning the source water on and off all the time, that may be hard on your membrane as well. Your aquasafe should've come with a pressure switch that turns the water on and off automatically without letting the membrane dry out.

[sharuq1]

Thanks for all the great advice everyone.

Where could I buy a new regulator and membrane for this unit? It is going to be some time before I can actually buy anything at all (sooo broke), but when I can at least I will know where to go.

[morph]

Hi there This is my understanding of flushing the membrane Just before your waste water moves away from the body of the filter Should be the yellow hose there is a white thing clipped on to the filter it has a black handle . the handle should be turned across the direction of the pipe to make ro water you would think your turning off the filter but thats how it works. to flush the membrane turn the black handle the same direction as the pipe let the filter continue to make water for about 20 minutes threw out that water . now turn it back across the pipe do this once a month

[sharuq1]

That is also what the instructions say....the reson I was confused is because my unit doesn't have that black handled thingie, it has the metal turnie one.