ro/di 150gpd upgrade and booster pump?

[acidtablockshifty]

Any one know a thing or two about ro/di system/ setup? I just got in the 15ogpd upgrade for the brs 75 and i ordered a booster pump, i have two maybee three questions.

1- instead of running a mini pre-filter screen on the booster why couldn't i just put it between the sediment and carbon block?
2- will i need to restrict the pressure some after the pump is setup, pressure is around 62psi right now i have know idea what it will be after the pump is hooked up?
3- running the two membranes in series questions-
the way its setup right now just 75gpd these are my tds readings
well tap tds- 402-426 depending on the day
product from membrane- 002
currently only setup as 75gpd
product from di canister- 000
waste water- 532

our water is very hard but is supplied through a softener and ends up very soft, so i assume that a lot of the tds is just salt in the water. If i set it up in series its basically taking the waste water and putting it through another membrane but i did the math(probably not right) and this way just wouldn't work for my system (tds out to di wise) i think? I guess my original goal was to reduce well pump running making the system more efficient but im starting to second guess that its going to work, and i am thinking i may have to run them not in series but parallel essentialy doubling my waste/ well pump usage with only benefit being quicker operation.

i dont know the ratio the system is working at right now i can test it if need be, making about 10 gallons in three hours or so pretty much on par with the 75 gpd rating

should i just not even try to use the pump/addedd membrane setup and sell it, i dont want to burn through di resin if the tds is going to be high going into it

 

[EDO]

I would contact the guys at BRS and explaing this to them and see what they say. I recently did the 150 upgrade and hooked it the way BRS recommends and it works great. I have the booster pump because my house water pressure is low but if your getting 62 psi I don't think you need the booster pump.

 

[AZDesertRat]

You really will not need both a booster pump and dual membranes. With the booster pump alone you will get 125-150 GPD at 90-100 psi and at a better rejection rate or removal efficiency that with dual membranes.
The other issue is most booster pumps are not sized for two membranes so will be oevrworked trying to keep up. The industry standard Aquatec 8800 RO booster is only rated for a maximum of a 100 GPD membrane since once boosted it about doubles that. Two 75 GPD membranes set up with the correct booster would around 300 GPD + waste which the 8800 cannot produce.

I have been using an Aquatec 8800 and a single membrane for about 7.5 years now on softened tap water with a TDS averaging 560 and get an RO only TDS of between 2 and 3 and 150 GPD at 95-100 psi on the booster. DI lasts over a year on my MaxCap DI and three years on the SilicaBuster DI.

I would return the dual membrane set up and keep the booster if it were me. Dual membranes ARE NOT water savers contrary to what some vendors may tell you. They give you treated water faster but it is even more critical that you keep the waste ratio us since the send the concentrated brine from one membrane into the other. Long time RO vendors with lots of practical experience all recognize this and never promote dual membranes as a wate rsaving device.

 

[acidtablockshifty]

so if i did use the 150gpd i would just be looking at exhausting that new membrane much quicker and possiblly di resin much quicker. so what will my tds be after the membrane is being fed with 534tds water, you said your water come in at 560 and between 2-3 going out wouldnt my dual membrane have roughly the same numbers, as the waste water going in would be 532 plus 002, and ill be running at like 90psi vrs 60.

the other major reason for the booster pump was to sort of maintain water pressure because if i would make water while others used the water the pressure is always dipping below 40

this may sound crazy but would it be possible to put a check valve on the carbon block feed and a y after the check valve, take the waste from the first membrane and put it back through carbon, and then through the second? or am i losing my mind?

 

[AZDesertRat]

No two sources or water are the same so your numbers may vary from mine. What I am saying though is the booster will not keep up with two membranes, it is not physically or mechanically capable of doing so by design from the manufacturer, read the manual and pump curve that comes with it.

Not sure what you are trying to accomplish with running brine through a carbon filter? Sediment and carbon block filters are anywhere between say 0.5 and 5-10 microns in size, TDS or dissolved solids are 0.0001 microns and smaller so pass right through those and why a membrane is necessary. It wouldn't work anyway since the tap water entering the carbon block is under pressure, 60 psi or whatever you have, and the brine is coming out of the membrane at basically atmospheric pressure or 0 psi.

 

[acidtablockshifty]

so i ended up installing the 150 gpd single membrane, 150 gpd flow restrictor, with the booster pump, i put the pump in between the carbon and membrane with a check valve right after the carbon, also a check valve before the whole system just because i have been meaning to do that. With the 150 membrane at 80 psi i was getting 20 out, so i thought well they tested it at 65 so ill lower the psi,... that just made tds go up even more. I then cranked it up to 100 psi reducing the tds to 15, id like to crank it up to like 125 but my gauge max is 100 and i don't want to exceed the 150 its rated at, also its concerning running that high of pressure that it may spring a leak/leak past float valves.

if i put the 75 membrane back in and try to say make 100 gpd with that, what would i need to do, i read something about trimming the flow restrictor tubing?, am i going to have to tinker with it testing the waste water ratio and pressures,or should i just leave the flow restrictor alone put the 75 in and run it at 90 or 85.

AZ i saw an older thread you said that you flush your membrane with di water, how do you go about doing that. Do you just put a three way valve and hook a pump to storage container? I was thinking about how i could do that before storing the membrane.

I'm a little disappointed in this membrane the guys at brs said they had just got a new 150 membrane with 98% rejection and i kinda thought it was going to be a dow membrane

 

[AZDesertRat]

Spectrapure tried the 150 GPD membranes about 8-10 years ago and quickly discontinued them, they could not get enough to pass their quality control testing and they would have ruined their reputation is what I was told. I was lucky enough to buy one of the few they did test and found suitable but I sold it in favor of one of their MaxCap UHE-100 ultra low waste systems.

I would return that membrane and invest in the Aquatec 8800 booster, no clones or off brands, and one of Spectrapure's Select Series hand tested and guaranteed 99% rejection rate 90 GPD membranes with a capillary tube flow restrictor. You can crank the booster up to 100 psi and get 150 +/- GPD at better than 99% rejection rate easily.

The MaxCap UHE-100 RO/DI system is much more than just using DI to flush the system. Spectrapure has developed a microprocessor controller which controls the timed flushing as well as double flushing with tap and then DI on shut down to dislodge any built up solids on the membrane so it is quite complicated with the microprocessor, booster pump, power supply and multiple solenoid valves and both 3/8" and 1/4" tubing sizes to get the volume and velocity to do the job correctly. People comment about the initial investment but I have yet to find anyone who purchased the system complain about its performance or its long term cost savings and return on their investment. It was a chunk of change up front but I can literally count the DI and filter replacements in the last 7+ years on both hands and zero membrane replacements.