Randy Holmes-Farley
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My Tank Thread
Flow Restrictor
- Thread starter Empress
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SVP
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So I have a question for either empress or phxrising. I have a spectrapure original manual flush 90GPD unit. So I have taken up RODI units a making my own/or upgtading sort of as a secondary hobby to reefkeeping. Last night i added a second TFC memrane my first being the spectrapure 99% rejection membrane the second being a dow membrane from Bulk. Before this upgrade I will give you the basics: I use ⅜ inch tubing from water source and the aquatec ⅜" pump and my first canister the front side is a ⅜" inlet at 90psi. I then run 6 premembrane cartridges so its 2 zeta cartridges for removal of particulates and then 2 pentek 1bulk & 2 chloramine blasters then my first housing reads 90psi at 255 tds my second membrane drops to 85 psi and after it my ro is at 5 or 6 depending upon the time of the day so after my 3 di cartridges im getting over 225 GPD at zero tds. I have yet to see my waste ratio but i never thought that adding the second tfc membrane and turning my psi up 10 more pounds could have that drastic of an affect and would produce that much water. Have you ever seen or heard of such a high output of water? I'm wondering /I know im burning through the mega silica blaster. Other things that i should look for? Im thinking something is wrong but ive triple checked everythingI don't access my emails on the weekend but if you do need me PM me on Reef2Reef!
Glad you love your unitI love mine too <33
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Excellence Award
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
Can you clarify how the two RO membranes are plumbed between the prefilters and the DI?
They are in series (one after the other) or in parallel (both going between the last prefilter and the start of the DI()?
It sounds like you have them in series, which is not generally a good plan and is very complicated (where does the waste before the second one go? How do you get adequate pressure to it without backpressure on the first?, etc.).
They are in series (one after the other) or in parallel (both going between the last prefilter and the start of the DI()?
It sounds like you have them in series, which is not generally a good plan and is very complicated (where does the waste before the second one go? How do you get adequate pressure to it without backpressure on the first?, etc.).
I'd like to see how your system is plumbed. Page 3 on http://spectrapure.com/manuals/PBK.pdf has a good diagram on how to plumb them both. I would say check your waste to product ratio as well. Can you provide the following;
Actual water temperature:
Waste flow rate in ML/MIN:
Product flow rate in ML/MIN:
Incoming tap TDS: 255
membrane pressure: 90
I use this to calculate membrane performance http://spectrapure.com/manuals/CALC-FORMULA.pdf
SVP
Active Member
The waste water from the first memranec is the input into the second membrane instead of flowing through the electric flow restrictor and down the drain. I apologize for the delay guys and I appreciate your response.
