SpectraPure

For last 4 years I use 90 gal. per day SpectraPure RODI. When my TDS reaches 0.01 then I'm replacing my Sediment, Carbon and DI resins. Did't replace RO membrane yet but I will this time. My question is really simple. I have always replace them with SpectraPure brand but they are quite expensive, for 4 of those cartridges I will pay around 140 $ ( best they have) Do you guys have suggestions or should I stick what works for me? I don't want to compromise health of my tank but just looking to save some money… Thanks for all advice.

 

I have used other brands and do not recommend any other brand than spectrapure. I would go through resin 3-4 times as fast as with the spectrapure as with other brands.

 

You really shouldn't need to be replacing all the filters at once as under normal conditions there lifespans will vary.
AZ Should be here soon to explain it to you.

 

I understand that I don't always have to replace them at the same time. It's just feels like just this time I should. RO membrane is almost 4 years old. DI - 8 months. Sediment and Carbon 4 months. Sediment is really yellow. That's why I'm thinking I need replace them all.

 

If you have a TDS meter check the water going into the membrane and then the TDS coming out of the RO only. If it is still pulling its rated amount out then the membrane is fine.

 

+1 you can also tell which actual filter is failing using this method.

 

Ok. I will check that tomorrow.

 

If you keep up with the sediment and carbon block replacements on a 6 month schedule or using pressure gauges and a low range chlorine test kit to extend the frequency and you have softened water, the membrane should last up to 10 years or more. I'm at 7 years on my membrane now with a softened tap TDS between 550 and 600 and the RO only rejection rate is still at 99.4%. How long or how many gallons does your DI resin last? Does it seem like the production rate has dropped off? This along with rising RO only TDS are the two signs a membrane is in need of replacement and usually it is slower production before higher TDS when they go.

What is your tap TDS, RO only TDS and final RO/DI TDS? (There are no decimal points, the dot is actually a power ON indicator light so the TDS is 001, 002 etc) Are you using softened water and/or do you know your calcium carbonate hardness? What is your exact measured waste ratio? What is your pressure and your water temperature? Do you make water in nice long filter runs versus frequent small batches? When the system is not operating do you keep it hooked up so it stays full of water or if you disconnect it do you make sure the housings stay full so the membrane and DI stay wetted?

 

Ok. Thanks for all info. Please help me understand all this and help me to figure out which cartridges I need to replace now and which I can wait and to what point. I think I have all answers for you guys and specially for AZDesertRat So my DI usually lasts about a year. I have 125 reef tank with 30 gal. sump. changing around 25 gal. every 2,3 weeks. My tap water quality is good as tap water can be. I live in Naperville il. TDS on tap water shows 140 ppm. RO only TDS - 0.03. RODI Water - 0.01. Ratio - 5.5 - 1. Temp. - 61.1. Pressure 50 ps, not great but still in range. Mostly I make 50 gal. for 2 water changes and 15 gal. for top offs in one long run but not always. If I have to leave house then I shut it off. System hooked up all the time.

 

If your tap TDS is 140 and your RO only TDS is 3 that means your RO membrane is in very good condition. That is a 97.85% rejection rate which is better than the average new RO membrane.
You should be replacing your sediment and carbon block filters every 6 months like clockwork and disinfecting the system at least annually. These are the steps that protect the RO membrane and about $25 for the pair in the 1 micron near absolute size from Spectrapure. I highly recommend 1 microns as the maximum micron size to use and if you want your membrane to last even longer and work better switch to the 0.5 micron size if you do not use them presently. The better the membrane is protected and taken care of the longer it lasts, better it performs and less it costs you to own and operate.

The membrane should last 5-7 years or longer, even 10 years if you follow those simple steps and in addition if you have a wate rsoftener make sure to use soft water to feed the RO since this is by far the best thing you can do for a membrane, they love softened wate rsince it does much of the work for them.

Another reason your membrane is doing so well is you are overflushing it at 5.5:1 waste ratio. You could easily get that down to 4:1 and if you have soft water even 3:1 or 2:1. By doing this your pressure at the membrane will go up since you are losing much of it down the drain now and your membrane rejection rate will also go up a little bit meaning DI will last even longer. Your owners manual has directions on how to trim and adjust the capillary tube flow restrictor. If you don't have your manual they are on the Spectrapure website here: http://spectrapure.com/Product-Manuals