TDS question

D

dannynguyen3573

New member
I just recieved TDS meter last night and I check for tap water the TDS show 265, when I check the water come form my RO/DI the DTS is 035. I replaced the membrane last 3 week (Desal Ã"šÃ‚® TFM-36 RO reverse osmosis ). My RO/DI system is Kenmore I don't know the model but it's has four stage.
Is there some wrong with my RO/DI ? What can I do to reduce the TDS number ? If TDS high, what cause the reef tank ?

Thanks
Danny
 
Your RO membrane should last for a few years, your prefilters should be changed every other month or so depending on how much water you make. As far as the DI filter it is hard to say as it depends on how much your RO pulls out first....some people can get close to a year on a DI filter and others only get a month or so . ........I would look at changing your prefilter and carbon block first and if that does not help then change your DI filter..... your TDS readings should be close to or at zero with clean filters
 
You source water is not as bad as mine, so you should be getting pretty good results. If you have a DI chamber after the RO you should be getting zero PPM or pretty close. Assuming your RO membrane has about 87% rejection rate now, your DI chamber should be doing something. I think you need to swap out your filters and DI if your didn't already, but you if you can test your water right after the RO membrane you can at least see how much your RO is doing, and then test it at the output to see how much your DI is doing. My guess is you need to change your DI.
 
I know where is pre-filter chamber but I don't know which one is DI filter, is that a carbon filter ? But any way I do change all the filter about 2 month ago.
Thanks
 
one more question, on the RO/DI unit do you need to shut off the vavle come from main water source (input vavle) or you leave it on 24/7 day ?
 
Most units have a auto shutoff valve built in. I know mine does. Are you sure you have a DI unit? If so it will be the last or second to last chamber if setup correctly.
 
RO units last for 6 months if you are lucky. I replace mine when I get a 20 tds reading. If you did not replace your other filters you can shorten the life of your membrane.
 
If you have a Kenmore unit you probably do not have a DI filter unless you installed it as an add on. More than likely what you have is a unit with a prefilter and granular carbon filter in housings below, a RO membrane which sits horizontally above that and probabl a small granular carbon post filter that is attached to the membrane on the very top.

If that is the case, try disconnecting the line from the RO membrane to the small post carbon filter on the top and test your TDS from that point. I will almost guarantee the TDS will be lower.

If you use the RO for drinking water as well as aquarium water, install a tee fitting between the membrane and that post carbon and attach a 1/4" line and valve to it. You can use just RO water at this point or buy yourself an add on DI filter from someplace like www.purelyh2o.com for less than $30 and have RO/DI which will be better than RO alone.

Prefilters and carbons should be changed every 6 months, an RO membrane should last about 3 years of normal use and DI needs to be changed when you see your TDS begin to rise above 3 or 4.
 
AZ has the same unit I do,

The Tyhpoon III from airwaterice.com

Great unit, good price, excellent customer service.

Mike
 
Assuming your unit uses 1/4" tubing (icemaker supply type tubing):

- If you are using your RO only to feed an icemaker/drinking water/whatever, get a 1/4" John Guest (JG) tee. Hook that to the output of the RO membrane. On one side of the tee put a JG valve, then pipe that to your icemaker or whatever. The other side of the tee, add a JG valve, then tubing into your DI chamber. More tubing and another JG valve on the outlet of the DI chamber and there you are.

Mike
 
Ok, last night I just recieve the add on unit from purelyh2o and pressure gauge, I haven't test on the TDS yet but my pressure is only at 30-32PSI. Is that right?
Thanks
 
Here is my hook up, please tell me if I'm doing wrong.
Tap water-->prefilter-->automatic vavle-->RO membrane-->membrane out put to store tank and post filter-->fauce water.
The post filter either split to DI champer-->the sum.
There is a drain flow come out from membrane champer too.
I put a spliter from the out put of membrane, one end go to postfilter and the orther end go to pressure gauge.
 
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