new ro membrane

My tds from my tap is 450. Tds after ro 5 , after di 0. Have a 4 stage vertex ro hooked to house for water/ice teed off to di for fish. Thinking of buying a 75gpd from bulk reef supply already have carbon and sed filter. Some plumber told me that if you get a higher gpd I have 35 now, your tds after ro will be higher? Hate waiting forever to fill 5 gallons. But if this is true I will keep my 35 gpd no name membrane thats in there.

 

Why don't you create a storage bin and make up large batches of Rodi? I use a 30 gallon cooler box.

 

That's s good idea. The thing is if I make 5 gallons my house dnt have ro and I have to wait like 2-3 hours to get more water. I guess I could get 30 gallons but that would take me like a week lol..

 

Thats BS as long as you do not buy the Dow Filmtec 100 GPD you are good.I w2ould suggest Spectrapures hand tested Select series 90 GPD membrane and matched flow restrictor for $45 and $5.
There is no reason you can't use what you have now though and separate the RO drinking water from the DI with a check valve as in the linked drawing. Its done all the time.
http://www.spectrapure.com/huds/4-STAGE-DWK-RODI-NAG.pdf

Note the placement of the tee and check valve so the pressurized drinking water cannot get back to the DI on a separate circuit. This is the desired hook up so TDS creep in the pressure tank doesn't kill your DI resin. Use some sort of storage container like a Rubbermaid Brute and a float valve so when the storage is full and the float lifts the ASOV senses backpressure and shuts things off same as with a full pressure tank.

 

Other than the slow production, your current membrane is operating well - you have a 99% rejection rate. That's uncommonly high. But even with decent water temperature and high pressure, it wil be s l o o w.

You didn't mention what size tank you have - if it is small, and if you got a reservoir as mentioned above, you would probably still be alright with you current membrane. But when it's time to replace it, by all means, go for a 75 gpd.

Russ

 

Thanks for the replys. That drawing helped alot. Did not know about the check valve at all. Glad to hear that's bs. Its a 75 gallon. Was going to change everything but hearing that its doing so well I will wait, its only 6 months old just sooo tired of waiting for water lol. Will check out that 75 gpd you suggested. Right now have 2 tanks, kinda like the drawing with no check valve .. pic to give you a idea. Thanks for the help.

 

Get that check valve and separate the pressure tank and its stored TDS creep from the DI circuit, your resin will thank you for sure. You will probably need to make DI water overnight it will take so long but worth the few $$ it costs and really its a cost savings since DI will last much longer and need fewer replacements.

 

That's great. Thank you, was wondering why my di was 3/4 exhausted and I have only made like 150 gallons of water. Thanks for your help