Another RODI Water Quality Question

[MadReefer]

Hate to hijack here but saw something that caught my eye. It stated that RODI should be 0/2 for use. I have a brand new RODI and my tap measures 137 and the best I could get from the unit was 5/6. Are you syaing that this isn't good enough to use? Am I just wasting my time making water?

 

[stcreef]

Hate to hijack here but saw something that caught my eye. It stated that RODI should be 0/2 for use. I have a brand new RODI and my tap measures 137 and the best I could get from the unit was 5/6. Are you syaing that this isn't good enough to use? Am I just wasting my time making water?

If you are truly measuring 5/6 from a new unit, then something is wrong. Start another thread and I'll see if I can help you narrow it down. Or if a mod can split this off.

 

[MadReefer]

stcreef,
I borrowed the TDS meter, hand held, and will have to again and double check the numbers.

 

[stcreef]

You'll want to make sure the TDS meter has been calibrated. Then measure 3 things.

1. Before the RO/DI
2. Between the RO and DI
3. And after the DI

What unit do you have and do you know how many GPH it is supposed to be. Even better would be the model number on the RO membrane.

Another thing to look at is the water pressure supplying the RO unit.

 

[Hawkeye]

Hate to hijack here but saw something that caught my eye. It stated that RODI should be 0/2 for use. I have a brand new RODI and my tap measures 137 and the best I could get from the unit was 5/6. Are you syaing that this isn't good enough to use? Am I just wasting my time making water?

If you are truly measuring 5/6 from a new unit, then something is wrong. Start another thread and I'll see if I can help you narrow it down. Or if a mod can split this off.

No hijacking... ;D

thread has been split. ;D

and I can lend you my TDS meter friday if you're around....or just wait until monday.

 

[stcreef]

Thanks for splitting it Phil...........

 

[MadReefer]

Yeah Phil tahnks for the split. Just for the record I was going to create a separate thread. I won't be in the office Friday. I'll PM over the weekend if I don't get tested by Monday. thx

 

[MadReefer]

Here is a pic of the unit by Pure water. I'll search the web for more specs.

 

[MadReefer]

Here is what I purchased with out the replacement parts. I bought it on enbay from Purewater club
http://cgi.ebay.com/Zero-0-ppm-Reef-6st-Reverse-Osmosis-RO-DI-0-5xFilters_W0QQitemZ120318438410QQihZ002QQcategoryZ20684QQcmdZViewItemQQ_trksidZp1742.m153.l1262

 

[calaxa]

5/6 is not bad but given your tap is reading only 137 I would have imagined you would've had 0 TDS reading. Maybe the DI resin is spent and 5/6 is from RO only.

 

[Hawkeye]

the specs read:

1 x sealed TFC (made in USA) 100 GPD RO Membrane

no model number - but it's 100 gallons per day.

 

[stcreef]

First, I dont recommend the 100gpd membranes. For some reason, the Filmtec/Dow 100 gpd membranes only reject 90%, most of the other membranes operate at about 98%. So if you are seeing 137 TDS in you will see 13-14 TDS out with the 100gpd membrane. This just makes the DI work harder which means it will deplete sooner.

Secondly, I dont recommend those tiny DI carts as seen in the pic. (which is the one with the blue endcaps). If the DI is spent, I would upgrade to a 10" DI filter.

Third, the filter above the DI is a GAC cart and needs to be removed. No filter should be after the DI unless you are only using it for drinking purposes. This will add TDS to the water for taste purposes.

So if your water in is 137, out of the RO but before the DI should be about 13-14 TDS. If it is higher, try flushing the membrane for 10 minutes. If its still higher, its time to change membrane. It will only get worse. If it is 13-14 or lower, then measure whats coming out of the DI. If its above 0, its time to change the DI. I know some people say 0-5 is fine, but once a DI cart is saturated, meaning your starting to get a TDS reading, its not doing anything anymore. And the level is only going to climb with every gallon of water that runs through it. So if you get anything other than 0 out of your DI, its time to change it.

Another thing to check is the water pressure going into the RO/DI. This should usually be above 50psi. Anything lower and the membrane will not operate efficiently. In other words, the TDS coming out of the unit will be higher. They are meant to be operated at about 65psi.

Now as far as the membranes go, the 50, 75 or 150 all reject 98%, but the 150 requires a higher water pressure feeding it. The 75 GPD is fine for most apps. If you replace your membrane with a unit that is rated differently than you already have, you also have to replace the restrictor valve as well. (In the pic, its the flush valve on the waste line, its a combo flow restrictor and flush valve)

I know that is a lot to digest, so I will answer any questions you have.

 

[MadReefer]

stcreef, thanks for all the info. You are the second person that said to remove that one cartridge. If the DI is already spent in making only about 65 gallons of water is that normal? I don't know the water pressure; all I know is it's considered high.

 

[stcreef]

If your DI is spent after only 65 gallons, then high TDS has been hitting it, which is NOT normal. Get the measurements before we jump to any conclusions.

 

[calaxa]

I didn't read through this carefully earlier, but how old is this unit? How do the prefilters look? Did you get the TDS reading at each step?

Initial 137
After prefilter ?
After RO ?
After DI 5/6

Hopefully it's not the RO membrance. What I hate about these systems is, buying a new RO membrane costs almost the same as buying a new unit.

 

[MadReefer]

It is brand new; got a few months back and hooked it up in October. I didn't tale reading after each I will do that as soon as i can get my hands on a TDS meter. I don't own one yet.

 

[vangvace]

check walgreens. They had TDS meters for sale for $15 in with their water filters. You might be able to get it from Walmart also, but I've never checked.

 

[grbspecb]

How did you make out.

I have well water that comes in at 600 TDS or higher. I run a ro/di filter with 3 large pre filters the ro and then 2 di. I ususally have about 5 tds through the ro and 0 through the 2 di.

I recently purchased some new DI as I was starting to see 5 tds. Now back to 0. Is the last filter on the top charcoal. I heard those sealed charcoal could be not so good and maybe remove it and replace with another refillable di unit. I had a previous system with the charcoal and it caused problems.