Ro/Di prices

You DO NOT want a so called "water saving" system if it is simply two 75 GPD membranes with the waste ratio reduced. As anyone who knows about RO membranes and the one thing they should all agree on is membranes must be flushed. Those who promote them as water savers are doing you a disservice and have no idea what they are talking about.

The idea of reducing the waste ratio has been tried and failed for decades, those who have been around that long have all tried it and gave up on it years ago, it does not work for long and the membranes will fail prematurely, especially the second one in line. Think about it for a minute, you are sending the concentrated brine from the first membrane to the second membrane so the TDS is already much higher than the tap water was to begin with. Why would you reduce the ratio and make the brine even more concentrated.

Please talk to someone who knows what they are doing when dealing with RO/DI. The three vendors I recommended have all been around for over a decade and Spectrapure has been in business over 25 years and is the best in the business uncontested. No other vendor has the lab facilities and testing facilities or has tens of thousands of hours of testing under their belt. If it were as easy as reducing the waste don't you think every vendor would be doing so? It does not work and they will not subject their customers to something that doesn't work and would come back to bite them.

You do not want inline TDS meters, they have limitations and are not nearly as accurate. You lose the portability and accuracy of a handheld which can test anywhere, not just two dedicated places. You can test the tap, RO only, bottled water, the LFS water, RO/DI, vending machines, etc. The inlines cannot do this plus read air temp and not water temp so can be significantly off since they are rarely the same.

You do not want so called chloramine filters, they are a rip off. Chloramines are a walk in the park for a good 0.5 or 0.6 micron carbon block, yes a single block not two and definitely not granular carbons. It is the ammonia portion that is the problem and carbon does nothing for ammonia, that is where good reef specific DI resins come into play. Spectrapures SilicaBuster is blended with chloramines in mind and does not come any better.

Please be careful who you listen to when it comes to all things reef related, many people will speak like an authority when they are really misinformed. They are trying to help but the information is not correct.

 

FYI - I was merely stating what I have and for what it cost. You are correct in how the the water saving works, however my tap is relatively low TDS to begin with (75-100). Post RO is between 2-4 (~96% rejection rate). Obviously the second membrane will fail before the first, however if it lasts a year, than it is worth it IMO. And you can certainly replace the carbon block with a smaller micron after it is used (or even before). It comes with a 1 micron block. Do you really think there is no benefit to having GAC before a carbon block? At worst I would think it would reduce contaminants going to the carbon block, which will increase its life. Curious to hear your thoughts.

Either way, good information on everything you posted. We are both in the water/wastewater business, and it amazes me how much the knowledge can be shared between work and home with a hobby

 

GAC in front of a carbon block is bad as the granular carbon pulverizes and turns to fine dust as it exhausts. The result is plugging of the billions of tiny microscopic pores in the block quickly rendering it useless. The pores are where the chlorine and VOC's are trapped so it is imperitave you keep this surface clean and protected.
The old idea of a 10 or 5 micron sediment filter is old school and testing shows it is too coarse to protect the carbons pores. Use no larger than a 1 micron sediment filter, 0.5 or 0.2 microns is even better, and an absolute rated filter is much preferred over a nominal rated filter, there is a huge difference in their ability to trap silt and colloidal materials which most people are not even aware of.

 

:thumb_up: Wow, great info! I will keep all of this in mind when I replace my current filters in the near future. I imagine with that small of a sediment filter, you would need to replace it quite often. But they are cheap and easy to replace anyways.

 

I use the pleated 0.2 micron ZetaZorb which has 10x the surface area of a normal spun poly type filter and it easily lasts 18 months, not that I recommend most people do that.
I have pressure gauges both before and after my sediment and carbon filters and monitor for headloss, fouling or plugging of the sediment filter plus I use a low range chlorine test kit and monitor my carbon block for signs of chlorine breakthru so I am comfortable doing so. I see no more than a 2 psi drop in pressure after the 18 months but am not comfortable stretching it past that point. In my experience it filters better, lasts longer and has less pressure drop than a normal filter so is more cost effective.
I will not use cheap or inferior filters as my personal experiences both at home and at work are not satisfactory when doing so.

 

Well if it lasts that long, it is well worth it. I currently replace my spun poly filters every 2 months. Final question for you. Would you see any benefit in using a cheap 5 or 1 micron sediment filter before a ZetaZorb?

 

Normally no.
Every filter, fitting, component, etc. you place in front of the ROmembrane has an associated headloss which reduces the efficiency or rejection rate of the membrane. This is another reason I discourage multiple carbons when a single carbon can and will perform a better job with less pressure loss.

If silt or sediment are a problem there are washable or backflushable filters available but i wouldn't use one unless I had to unless you have sufficient pressure to overcome the headloss, such as using a booster pump or raising your pressure regulator setting if you have one.

 

Understood. I am lucky in that I see 85 PSI at my RO unit. When I get new filters in about two months I will try leaving one stage empty, one with the .2 micron ZetaZorb, and a 0.5 micron carbon block and see how it does. Thanks for all the info, and hopefully onlookers are learning as well!

 

I have the $128 refurbed 90 gpd unit from Spectrapure with a booster pump in between the carbon block and the membrane. I run the pump so I have 100 psi going into the membrane and it produces about 170 gpd

I could not be happier with this unit, I have owned some poor units that I had payed triple what I payed for the Spectrapure

 

Alaska! i'm wild about Alaska, GOD I WISHED I HAD STAYED THERE. So whats the weather like there in the land of the midnight sun? get some spring water out of the many mountain springs all over the place, I believe you can't get a more purier water than Alaskan Mountain Spring Water.