RO options

[beaker77]

I have a SpectraPure RO system that was 25 gpd and I upgraded it to 100gpd and added a DI canister about four months ago. My TDS has never been below 2ppm and now it ranges between 6-8.

I'm going to replace the 100gpd membrane with a 50gpd membrane w/ flow restrictor and change the DI resin.

My question is:
Would I be better off adding a second 100 per day membrane instead of one 50gpd?
Am I missing something else as to why my TDS is so high?

Thanks

[capncapo]

Have you let it run for 10 minutes and then checked your TDS?

[beaker77]

Originally posted by capncapo
Have you let it run for 10 minutes and then checked your TDS?

Yes, I normally check the TDS after it's been running for around an hour.

[chadfarmer]

get a 75 gal a day membrane

[beaker77]

Originally posted by chadfarmer
get a 75 gal a day membrane

Thanks Chad, that's what I'll do then.

[Unresistible Blue]

Originally posted by beaker77

My question is:
Would I be better off adding a second 100 per day membrane instead of one 50gpd?

Hmm. I'm confused. If you configure your system with two 100 gpd membranes, you'll have a 200 gpd system.

If you use a single 50 gpd membrane - you'll have just that - a 50 gpd system.

So - if what you ended up doing is replacing your current 100 gpd membrane with a 75 (and a matched flow restrictor, I assume),
then give us your tds levels in three locations as a start to troubleshooting the system:

tap water tds?
post RO (pre DI) tds?
post DI tds?

[Thefilterguys]

Originally posted by beaker77
I have a SpectraPure RO system that was 25 gpd and I upgraded it to 100gpd and added a DI canister about four months ago. My TDS has never been below 2ppm and now it ranges between 6-8.

I'm going to replace the 100gpd membrane with a 50gpd membrane w/ flow restrictor and change the DI resin.

My question is:
Would I be better off adding a second 100 per day membrane instead of one 50gpd?
Am I missing something else as to why my TDS is so high?

Thanks

The rejection rate on your 25 GPD was 98% giving you a TDS of 2. You changed to a 100 GPD with a 90% rejection rate and it went to 6-8 is this correct? What is the TDS of your raw tap water?

Now you want to change membranes again. I suggest you can go to a 75 GPD and still get the 98% rejection. You should be down to zero TDS with your DI. Are you using a vertical DI housing? You may want to consider adding a second DI housing to get that zero reading. If you were getting zero at one time you 100 GPD is just exhausting your resin faster and it time to change resin.

Jim

[beaker77]

Originally posted by Thefilterguys
The rejection rate on your 25 GPD was 98% giving you a TDS of 2. You changed to a 100 GPD with a 90% rejection rate and it went to 6-8 is this correct? What is the TDS of your raw tap water?

Now you want to change membranes again. I suggest you can go to a 75 GPD and still get the 98% rejection. You should be down to zero TDS with your DI. Are you using a vertical DI housing? You may want to consider adding a second DI housing to get that zero reading. If you were getting zero at one time you 100 GPD is just exhausting your resin faster and it time to change resin.

Jim

I never had a TDS meter when I had the 25gpd membrane. I purchased a 100gpd membrane, TDS meter, and a vertical DI canister all at the same time. When I purchased the 100gpd membrane I didn't realize that the reject rate is so much worse, When all was new I was getting 2 ppm after DI. My tap water is between 115-130ppm TDS. The 75gpd membrane has been ordered. I'll get a second DI canister if I still don't hit 0ppm TDS or do you think there may be another problem if I'm still not getting 0ppm TDS with a new membrane and new DI resin?

[Thefilterguys]

Ok here's where your going to be at. You should get a TDS of two to three coming off your 75 GPD membrane hoping you bought a Filmtec. If your using a full sized vertical housing Your DI resin should produce over two thousand gallons of zero TDS water. Check the TDS of your ro water once you get your new membrane and see if this is correct.

Jim

[beaker77]

I installed the 75gpd Filmtec membrane today. 0 TDS for the first time!!! Thanks for everyones help.

[Thefilterguys]

Brian

[levon15]

Nice work