Is it membrane time? Got new one?

[cichlidtx]

I've been using my Spectrapure CSPD for 4 years now. I added a boost pump in April as my water pressure was running around 40psi and taking almost 2 hours to produce 5 gal. With the addition of the pump my pressure is now 80-85 psi and just a tad over an hour to produce 5 gal. I changed all filters and the DI resin at the same time. My TDS is now reading 1 in only 3 months. Can the added pressure have had an affect on the membrane. Based on reject rate calculation its now 79%.

Tap - 133

RO - 27

TDS - 1

 

These numbers were all confirmed using handheld HM-4TMA. I just need some confirmation that I need to order a new membrane. I hope I covered everything, thanks for the help.

[AZDesertRat]

If a handheld meter confirmed those readings then I would say it is new membrane time.

Two questions I have though are what is your exact measured waste ratio and are you using softened water if you have it available?

 

With a tap TDS of only 133 I am extremely surprised the membrane is shot so soon, this is why the question about the waste ratio. If it has been flushed well at say 3:1 to 4:1 waste ratio and you have kept up with the sediment and carbon block replacements, disinfected it annually and never run hot water through it I would expect 10+ years out of the membrane. With softened water even longer.

 

I run my booster pump at 95-100 psi, use softened tap water with a TDS around 560, the RO only TDS is between 2 and 3 and my system is almost 7 years old now on the same membrane.

[cichlidtx]

AZ, thanks for the response. I've been running a 4:1 ratio and I'm not using softened water. The water here is hard. I thought this was premature, but i will have to admit that I haven't been disinfecting as required. I have changed the sediment and carbon block twice a year though. I have not been using Spectrapure filters/carbon block for the last 2 years but a competitors. I don't believe that's the issue.

[AZDesertRat]

Yes, that is a big part of the issue.

 

Spectrapure has spent decades testing every filter and carbon on the market and only put their name on the very best. Their replacements are either absolute rated or near absolute and no larger than 1 micron with the better filters 0.5 or 0.2 microns absolute rated. There is a huge difference in effectiveness, many use as large as 10 micron and others 5 microns. That is like 10 to 20 times more coarse than a 0.5 micron and about as effective as a screen door for protectinb the membrane. The sole purpose of the sediment and carbon filters is to protect the membrane, thats it. You might not know but you can see 40 microns with the unaided human eye so 5 or 10 microns and nominal versus absolute is quite large and not too effective.

 

I wouldn't even consider anything but a 0.5 or 0.2 micron ZetaZorb sediment filter and a 0.5 micron 20,000 gallon carbon block, its throwing money away if you don't as you have found out.

 

My personal system is a good example or how well a system can work and how long it can last with the proper filters and minimal maintenance. $25 for a set of 0.5 filters is pretty cheap compared to a new membrane every 3-4 years.

 

You might consider looking at a water softener to protect all your plumbing, including the RO and cut your soap usage drastically. Although with a TDS of only 133 it can't be very hard, even if that were all calcium carbonate that is only like 8 grains of hardness, ours is around 18-20 grains.

[cichlidtx]

Thanks AZ, I will order new filter, carbon block, DI, and membrane. Lesson learned not to skimp on quality as we invest a lot with our corals. I have a few more questions.

 

Is there any specials going on at the moment?

Is the tested RO membrane needed for the extra $20? Got tuition to pay for son and every penny counts at this time..

Should I get the preset flow restrictor while I'm at it?

[AZDesertRat]

You would need to check their site for specials, I am an end user like yourself so have no inside track. They seem to have specials all the time though and you might also check Marine Depot and Premium Aquatics, they both carry Spectrapure products, often have sales and usually have reduced or free shipping which may save you some money.

 

When you consider a RO membrane can last 10+ years if taken care of then Select series 99% rejection membrane makes a lot of sense. For every 2% you increase the rejection rate, say from 97% up to 99%, you double the life of your DI resin. So just one DI lasting an additional 6 months or whatever has paid for the Select membrane and from then on its money in the bank.

Get the untrimmed capillary tube flow restrictor and trim it to fit your unique water conditions once you get everything installed.

[cichlidtx]

Thanks again for the help, I placed my order this evening. Now I need to search for disinfecting procedure.

[seabass]

Thanks again for the help, I placed my order this evening. Now I need to search for disinfecting procedure.

http://www.nano-reef.com/topic/254034-cleaningsanitizing-rodi-unit/

[cichlidtx]

Thanks, I appreciate it. I just found that a few post a few minutes ago.

[cichlidtx]

Ok, I replaced my membrane. The old one had slime on it and smelled fishy. I disinfected the entire system with bleach and rinsed completely. I replaced all filters as well as the DI. I'm in the process of setting the waste ratio and have a question. I'm setting the flow restriction with the booster pump running (90psi). The 1st measurements were: 1000ml(waste)/350ml(Product)= 2.85. The highest value on the 90Gpd chart was 269ml/min and to trim to 1". I did so and here is what the 2nd measurements were: 1450ml(waste)/310ml(prod)= 4.6. Is this acceptable and if not do I need to trim the flow restrictor a little more. Thanks

[AZDesertRat]

With your tap TDS at only 133 the 2.85:1 is fine for a waste ratio. Thats about 3:1 which is percect with low TDS water. If your TDS was like mine at closer to 600 I would recommend the 4:1.

[cichlidtx]

Thanks, for the response. I already trimmed to the 2nd value of 4.6. I can order another restrictor if that's a better option in the long run. I appreciate your help in getting my RODI back in shape.

[AZDesertRat]

At 4.6:1 the membrane should last forever if you keep the sediment and carbon block changed as recommended and use high qualitylow micron replacements.

[cichlidtx]

AZDesertRat, I really appreciate your help. I ended up changing back to the old restrictor which is 4.5:1. I will make a point to change out the filter and carbon block every 6 months. This was a good learning experience, that's the thing about this hobby as you are always learning something new.