Hey Mike, I also read some of your old threads on this topic as well. I think I must have read the thread where yourself and Mika went over this topic. I haven't looked for the valve you mentioned yet but will do so probably tonight. I suspect I shouldn't have an issue with water pressure as my house is not lacking in that department.

I also just stumbled on a water saving upgrade kit from the same supplier.

http://www.bulkreefsupply.com/store/...grade-kit.html

I think I'm getting closer and closer to finding the solution that will work best for me.

Thank you all for your input. It is very much appreciated. I thought this is probably the very foundation on which I will build so I want to make sure it's done right the first time.

That upgrade kit works essentially the same way I am working my system except I am using one 150 gpd membrane instead of two 75 gpd. The way they do it is "safer" for the membrane, but I'm getting more efficiency. Also be aware that you need 65 psi through your tap for the water to actually come out at 150 gpd whether you use one or two membranes.

Split the line after the RO. Run one of those lines to your fridge, then the other to your DI (which then runs to your RO/DI storage container). I'm not sure how the plumbing on a fridge works though...do you have a pressure tank for it, or does it run off tap pressure?

This looks like a good idea for you, but I don't think you would need the pressure storage tank for your fridge...? I would think if you need a storage tank that you would already have it? I don't know much about plumbing the fridge.

Hi Mark

Thanks for the kind words. It's a little bit of 'smoke and mirrors' mixed in with lots of research.

As much as I'd really like to sell you one of the Vertex RO/DI units, I have to admit that the BRS unit is probably what you are looking for. Keep us in mind for any of the other things you might need.

I'm impressed by how much feedback this thread generated. There are some really good ideas posted.

I'd personally recommend an inline TDS meter vs. a hand held one. Other than that, I think you are on the right track.

Thanks

Brad

Brad, why do you like inline TDS meters better? Do you sell one that can be calibrated by the consumer?

Hi Myka

As of yet, I don't think we stock any TDS meters. That said, they kind of go hand in hand with RO units, so perhaps we should.

I own two dual stage inline TDS meters. Both can be calibrated, but i have never done so. Personally, I'm not as interested in an accurate reading as
I am about a change from a known baseline parameter.

If my tap water is 100ppm or 200ppm, I don't really care. It is interesting to see if in the spring with the snow melt and run off the TDS increases, but it's not an important reading to me.

I am interested in the TDS between the RO and DI as well as the TDS between the DI and the Resevoir. These measurements tell me when to replace my membrane and when to replace my resin. With an inline monitor, I can see the effect of flushing the membrane in real-time and I can time how long it takes to reach peak performance.

For example, I know that it takes almost 5 minutes of flushing to bring the TDS down below 10ppm after the RO membrane, so I have a solenoid that flushes for 5 minutes once a day when the unit comes on.

I'm also not too concerned about whether my TDS is 0ppm or 1ppm as long as it doesn't start shifting too much. I know the calibration is reasonably accurate because when I change the DI resin the monitor reads 0ppm.

For my application, these sensors really must be inline to be effective.

- Brad

Hey Brad/Myka/Blom,

Thanks for your input. It really helped quite a bit. I ordered the unit along with the pieces I think will be best for my needs. I did do quite a bit of research myself before I posted this thread so I'll also post what I purchased. I hope it will help others in their decision making.

• 75 GPD RO/DI 5 Stage Drinking and Reef Water System
• Membrane Flush Kit
• 150 GPD Water Saving Upgrade Kit
• Glycerin Filled Pressure Gauge 1-100 PSI
• Dual Inline TDS Meter DM-1 HM Digital

I figure If I'm going to buy a reverse osmosis kit I might as well incorporate it into our drinking water if I can as well. That way it will save me on fridge, brita filters and whatever else I can save on.

I don't like wasting water so I purchased the Water Saving Kit.

The pressure guage I think was a cheap piece and if these things work better at a certain psi I will know what psi I have in my house.

Brad, I agree with what you said about the Inline TDS Meter. Knowing when to flush/change your filters is key to getting the most from your RO unit; both after the RO stage and after the DI stage. Who wants to be playing guessing games with their equipment. Taking the guess work out is key. Plus it was a cheap add-on.

Thanks and I hope this will help others.

Mark

Sounds like you've made a great choice based on your research. Before this thread fades into the archives I thought I'd just mention that I find it useful to have two pressure guages plumbed into my RODI system, one before the RO membrane (generally the config with most systems offered with that option), the other right at the input. This allows me to monitor the pressure differential between the two and has proven a great way to determine the state/life of the pre filters. For the price of another psi guage, I've found it a worthwile addition.

Most recommendations I've seen on forums & from system vendors are to change the poly pre filters as well as carbon stages at certain time based intervals such as 6 months. While I'm not a RODI expert, this type of time based maintenance makes no sense to me. Logic tells me that I should be basing system maintenance on gallons throughput and this varies for everyone I'm sure. Yes, prefilters are inexpensive, but why not get full use out of them by monitoring parameters such as pressure differential & number of gallons produced? The clear filter housings are a good indicator of when pre filters need some TLC, but I believe the more reliable method is a dual pressure guage set up.

While my water provider maintains a generally reliable & constant pressure, there are minor fluctuations from time to time and with a single pressure guage, I may be inclined to think the system needs maintenance. Having two pressure guages helps mitigate that issue. With clean pre filters the pressure differential on my set up is between 18 & 20 psi, eg, guage 1 reads 86 psi & guage 2 reads 68 for a differential (pressure drop) of 18 psi between the input & the RO membrane. When this number approaches 22 psi, I know it's time to service the 5 micron poly pre filter. I've actually found taking it out, scrubbing the exterior and putting it back in restores performance to near new. Most of the grunge causing the pressure drop collects on the outer surface of the pre filter in my situation. When my 5 stage system was delivered it came configured with 5 micron poly pre filter, the 0.5 micron carbon chlorine guzzler, 1 micron carbon block, 75 gpd RO membrane & DI stage. After about a year of usage & monitoring I've removed the second carbon stage (not required since provider uses chlorine, not chloramine). Also moved the 0.5 micron carbon to stage 3 and added a 1 micron poly to stage 2. This configuration has been working great for me, YMMV.

I've added a worksheet to my Marine Aquarium Excel spreadsheet to track RODI system parameters, including gallons of water produced. It's been a great tool in maintaining the system. Better than two years running now and still on original DI media as well as carbon block & membrane. The 0.5 micron carbon block in my system is a rated for 20,000 gallons throughput at 1 gpm, so this is another instance where keeping track of your throughput comes in handy. I hightly doubt that most hobbyists produce that much water in 6 months, so why replace it at that interval? I've purchased a pool test kit which can measure chlorine & intend to test the water after carbon block soon though, just to ensure it's still pulling out the nasty stuff.

Finally (whew, turned into a bit of a novel here), having the drinking water option is a great idea. In Vernon I'm on the Kalamalka Lake source and we've been under a boil water notice since early September. This hasn't happened very often but being able to produce safe drinking water with my own system is coming in real handy right about now. Wine & beer making with concentrate is another activity that benefits from the pure water I'm able to make. Cheers.

Ah, very good Mike. I like this. :)