what the bazooka?...ro/di tds

temperature of the water is around 10 degrees. retested the in and out line, results as follow

IN is around 21 now (no clue why it read 100+ before) and OUT is 0 when pressure hits the 75psi, anything lower then 60 the TDS starts rising on my OUT line.

TDS on my WAIST line is 119-122

 

In order, what is your tap water TDS straight from the faucet, your RO only TDS taken before the horizontal DI and your final RO/DI TDS? You gave me two of the three and I don't know which is which?
What is the waste ratio, this is a critical measurement and the life of the RO membrane and DI resin depend on its accuracy. Use a measuring cup and a clock and watch to measure the flow from the waste line for exactly one minute. Then do the same for one minute with the treated water. How many m/L is each?

 

TDS reading of water straight from the tap: around 56
TDS reading of water just out of the IN line: around 21? (is it pressure that makes the reading drop? doesn't make sense)
TDS reading of waste line: 120
TDS reading of OUT line: 0
i unfortunately placed the unit back in its PITA reachable spot and really dont have the motivation to take my laundry room apart again ( a better solution is in plan) so cant give you the reading after the first 3 stages.

waste to RODI water ration in one min.

waste i collected 340ml
out or treated water i collected 40 ml

100Psi

 

What are you calling the IN line? The three places you need to sample are the tap water faucet or source, the RO only water after the RO membrane just before it goes to the final DI filter and the final RO/DI. The tap water TDS and the TDS after the sediment and carbon filters should be within 1 or 2 TDS of each other since they only remove silt, particulates, sediment, colloidal materials and the 1 or 2 mg/L chlorine residual in the water. The RO membrane is where 90-98% of the TDS removal is accomplished so if your tap water TDS from the faucet is 56 you would expect to see between 1 and say 3 coming out of the RO membrane and of course 0 after the DI stage if all is working as it should.

Your waste ratio is way too much also, you should be seeing a maximum of 4 waste to 1 treated, you are more like 8:1 so way too much is going down the drain which makes your RO membrane much less efficient since you are losing pressure to the drain. You probably don't need a booster pump if you get your waste ratio corrected at 3:1 to 4:1.

What are you using to test with? Hopefully it is a ATC or temperature compensated handheld TDS meter and not a dual inline which limits your testing ability and is not nearly as accurate since it is not temperature compensated and cannot be used portable.

 

sorry AZ i haven't forgotten you, will get back to you soon on this

 

No hurry. I'm here to help.

 

Thx AZ, its a relatively simple concept yet i can't seem to get my head around it. I apologies in advance for the machine gun like posts that will follow....

these are the PSI and TDS results i get after the first 3 stages, the cold water faucet is opened fully yet i seem to have pressure issues.

*text, Pressure sucks"

first three**...... -.-

 

results after the RO membrane.

 

and finally results after DI with a picture of the flow (I haven't timed it over a min yet)

 

You definitely have issues. First is your pressure, you need a minimum of 40 psi for a RO membrane to function efficiently and more is better. Second is the RO membrane is doing basically nothing for you as noted by the 124 in and 120 out TDS readings.


Try kinking or pinching off the waste line for a minute or so and see what that does to the pressure gauge. We already know your waste ratio is too high and you are losing pressure out the drain but lets see how much you have if you stop or slow the waste.

If the pressure rises significantly which I suspect it will then you need a new flow restrictor suited to your conditions. I would suggest a capillary tube flow restrictor you would then trim to get an exact 3:1 or 4:1 waste ratio, with your 124 IN TDS 3:1 should work good for you. If you have an extra ball valve or needle valve around you can use it temporarily on the waste line top achieve a 3:1 ratio.

Once the pressure goes up to the membrane its performance should improve. That 120 should drop significantly, if not you have either a bad membrane, a membrane that is not fully seated or a bad membrane housing allowing water to bypass the membrane.

The DI is probably already nearing exhausting since it has been receiving 120 TDS instead of the 2 or 2 it should be treating. I would not do anything with the DI until you get the RO figured out though as it would be throwing money away at this point.

The waste line TDS will be 20-25% higher than the tap water TDS since it contains the concentrated TDS from the treated water.

I sure wish you could get your hands on a handheld TDS meter with auto temperature correction, the inlines are next to junk since they are not temperature compensated and your water temperature and air temperature are rarely going to be the same. I have two dual inlines and have not used them in years, they never agree with the COM-100 and AP-1 handhelds I use instead.


EDIT: As I look at the photos I think you have lines switched. Take a close look at the END VIEW in this drawing, the WASTE should be the ftting closest to the outside edge and the PRODUCT or treated line should be closer to the centerline of the housing. It appears your Orange line labelled DRAIN is really the PRODUCT line? This would make a huge difference.
http://spectrapure.com/huds/MPDW-DLX.pdf