Rate of water degradation

[Jimmybob2614]

So around Christmas I changed my RO membrane, just checked my water this morning and its reading 006

My water from the tap is 450ppm, I'm using 2x10 inch pre filters, a 4040RO (1:1 W) with booster pump and a 5L DI vessel.

Does this rate of degradation seem normal for using about 1000L of pure a week? So around 6000L so far and it's on 006? 

 

[Iron Giant]

Doesn't seem normal at all, you say 6000ltrs but have you included the waste water this is something that needs taking into account as well not just pure production

 

[Jimmybob2614]

Doesn't seem normal at all, you say 6000ltrs but have you included the waste water this is something that needs taking into account as well not just pure production

No, I've used 6000L of pure so 12000L has gone through it 

 

[High-tower]

What does the water come out of the RO at? 5l is quite a small resin vessel 

 

[Jimmybob2614]

What does the water come out of the RO at? 5l is quite a small resin vessel 

Around 16 usually. I know that now but didn't when starting so it's what I have 

 

[Iron Giant]

Around 16 usually. I know that now but didn't when starting so it's what I have 

I'd say most likely the issue is your 5ltr di vessel which I missed when I read your post, check your tds after ro and before the di if the tds is the usual 16ppm then it's your resin that is spent 

 

[High-tower]

Resin usage is about right then just a little bit high.

You ought to be getting a better rejection rate from your ro 16ppm is 96% you should be getting more like 98/99% especially with a booster pump, so between 4-9ppm. Then your resin will last 2/3x as long.

 

[spruce]

So around Christmas I changed my RO membrane, just checked my water this morning and its reading 006

My water from the tap is 450ppm, I'm using 2x10 inch pre filters, a 4040RO (1:1 W) with booster pump and a 5L DI vessel.

Does this rate of degradation seem normal for using about 1000L of pure a week? So around 6000L so far and it's on 006? 

I'm not sure what your question is tbh?

If your membrane is producing pure at 6ppm before DI then your membrane is working great. It has a rejection rate of 98.66%.

If 6ppm is after DI then you need to change the resin.

Your membrane will never remove all the tds from your tap water.

As far as prefilters are concerned, you need to identify what prefilters you are buying and what their service life is. For example, a 10" Fiberdyne carbon block CFB-Plus 10 filter has a service life of 37800 litres at 3.8lpm and a 20" CFB-Plus 20 has a service life of 75,700 litres at 7.6lpm. (The service life of a carbon block filter is the total amount of water your r/o uses; waste + pure.) This is why I believe that a 4040 r/o should have 20" prefilters, especially as you are using a booster pump.

Some prefilters only have a service life of 6000 litres.

 

[spruce]

Around 16 usually. I know that now but didn't when starting so it's what I have 

Sorry, I missed this whilst working with an answer to your original post. As @High-towersays, your r/o is producing at 96%. With a booster pump could be classed as a little low but it could also be because of your waste to pure ratio. You might get a better output result if you opened the waste valve a fraction. 60% waste to 40% pure or somewhere in between 50/50 could be the sweet spot.

What we need to know is what membrane you purchased and what prefilters you use. See my above post in this thread.

 

[ched999uk]

Using Grippatank's resin calculator (https://www.grippatank.co.uk/resin_calculator) if your RO output is 16ppm then a 5 litre vessel would need it's resin changed at around 7,500lts of pure!!! So 6,000 is a little low but not that bad.