Best DI resin and RO membrane?

[wallysworld]

My RO/DI filter seems to only last about 2 months lately before TDS go from 0 to 24. I tested without the DI cartridge in and the TDS were 48 in and 20 out. That seemed like a lot still after the membrane? I did some research and found that TDS should be about 10% of the "in" flow aafter just the membrane. So it looks like my 8 month old membrane isn't doing the job. I have not flushed it until recent but it doesn't seem to make too much of a difference? What are the best membranes to use?
I see that the DI resin is truely what gets the TDS down to 0. My problem is the DI cartridge seems to only last about 2 months?
The cartridges are all Coralife except the carbon thats Kent. So whats the best resin? Should I get the refillable cartridge?

This is on a 125 setup to autofill and I do a 15 gal water change every 3 weeks.

Interesting thing is that when I see a little redslime start I know its time to check the TDS and sure enough they are up around 20. So what evr is making it past the filter is feeding the redslime it seems.

Thanks in advance!

Walter

 

[ClosetFishGeek]

The best membranes I have used have been the dow filmtec membranes.

 

[ZANYMASTER]

Kent is good as well.

 

[wallysworld]

Closetfishgeek, After some more research I agree with you. It seems everybody else just copies the Filmtec design and DOW was the first to make these membranes (FT30).

How about resins? I am going to buy the color changing resins however is there a difference between them? What's up with Nuclear...

Thanks,
Walter

 

[ClosetFishGeek]

Closetfishgeek, After some more research I agree with you. It seems everybody else just copies the Filmtec design and DOW was the first to make these membranes (FT30).

How about resins? I am going to buy the color changing resins however is there a difference between them? What's up with Nuclear...

Thanks,
Walter

Walter,
I have not used any of the color changing resins however you might want to give these guys a call. Everything they make is top notch and are very helpful. http://www.spectrapure.com/

Thane

 

[wallysworld]

I heard the same thing from a very realiable source something about Maxcap DI...
I'll check them out.

Thanks!

See you at AMW family day

 

[ClosetFishGeek]

I heard the same thing from a very realiable source something about Maxcap DI...
I'll check them out.

Thanks!

See you at AMW family day

No problem...:splitspin

 

[tomtoothdoc]

tds out should be only 2% of in value...providing you're using the 98% rejection rate membrane. throw away the 90% rejection rate one....it sux. dow filmtec membranes....the 75 gpd has higher rejection rate than the 100 gpd. (i forgot the exact # but something like 98% vs. 90%). i used to use the filter guys but now i use bulk reef supply since i order more products with them plus i get the mr member discount from the last group buy.

i also piggy back this on to my 75 gpd to make it into a 150gpd water saver model.....waste the same amount of water as a 75 gpd model.

http://www.bulkreefsupply.com/RO/DI...ving-150-GPD-RO-Upgrade-Kit/product_info.html

also they got a new membrane rated for 150 gpd at 98% rejection rate but waste more water than the 2x 75 piggy back system.

http://www.bulkreefsupply.com/RO/DI...-Membrane-98-Rejection-Rate/product_info.html

even if you don't need that much water, upgrading to a 150gpd will let you make water twice as fast in case of an emergency. you should also check your pressure, if it's less than 50-60 psi, you should add a pump.....i got well water and it made a huge difference.

 

[Buckeye Field Supply]

Looks like you are burning through resin quickly because your membrane isn't doing what it should.

Could be that it isn't seated properly, or could be that your pressure is very low.

Do you know what your pressure is at the membrane?

What is your waste to purified watr ratio?

Russ @ BFS