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About AZDesertRat

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    Water Wastewater Operations and Maintenance Consultant

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    Phoenix AZ

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  1. AZDesertRat

    Can I use my RO unit?

    Make 10-20 gallons of RO only water to the drain and see what the rejection rate is. Measure your tap water TDS and your RO only TDS to calculate the rejection rate. Tap TDS - RO TDS, divide that number by the original Tap TDS then multiply that result by 100. Example tap TDS 200, RO only TDS 4, 200-4=196, 196/200=0.98, 0.98x100=98% rejection rate or removal efficiency which is where you want to be. Another big concern is bacteria growing in the housings, take it completely apart and wash it well with mild soapy water and rinse well. Then reassemble the housings without any membrane or filters in them and run a couple spoonfulls of regular unscented bleach through them and let it sit a couple minutes with the solution in it before rinsing and installing the new filters.
  2. AZDesertRat

    RO/DI Plumbing

    As long as the copper/bronze/brass is on the tap water side it is not a problem. Never install any metallic plumbing past the RO membrane though.
  3. AZDesertRat

    Replacing DI resin- did I do it right

    Resin actually shrinks slightly with time. I would dump the resin into a container and stir it up, it may have stratified or one or the other, cationic or anionic has settled to the bottom. Mix it up then pour it back in the cartridge, tap the cartridge on the table or counter top a couple times to pack it down, add more resin, tap it against the table again several times, top it off and reinstall the foam ring and lid. You want it packed as tightly as possible so water does not channel or short circuit.
  4. AZDesertRat


    Spectrapure by far. Their refurbished system is only $125 or so or their starter kit at like $160 can't be beat with everything it comes with.
  5. AZDesertRat

    Is my Spectrapure MaxCap RODI unit normal?

    Perfectly normal. You will get all sorts of noises from the membrane, you are forcing water molecules through a semi permeable sheet of plastic under pressure. One thing you can do is pick the system up in your hands while it is making water and slowly rotate it around in all orientations to release any trapped air in the housings. Usually helps. As far as the DI canisters, after the membrane it is basically gravity so the canister level is dependent on the height of your exit line or water storage. Raise the line or storage and the level goes up, lower it and it goes down. No big deal, just make sure it has water in it when not on use to keep the resin fresh.
  6. AZDesertRat

    RODI setup suggestions

    Refurbished reef quality RO/DI from Spectrapure for about $125 and the add on drinking water kit from PurelyH2o for like $60 or so. Less than $200 invested and you have the best of both worlds, a real reef quality RO/DI and pressurized drinking water. The only things I would add are a handheld TDS meter and a 1/4" check valve to isolate the RO drinking water from the DI filter.
  7. AZDesertRat

    Overflow box confusion...

    No you don't, you still have a standpipe extending to near the surface. The level will not drop any lower than the standpipe suction level. The overflow box could fall off completely.
  8. AZDesertRat

    Overflow box confusion...

    Why do you think a bottom drilled overflow would drain the tank? That's not the case. You install an overflow box which extends to just bow the surface of the display. In my case with a bottom drilled 100G display the level it drops is 3/4" or 3.48 measured gallons. U or J tube style HOB overflows are extremely reliable. Look at the Lifereef website and read their write-up about never having a reported flood. Eshopps is almost identical. I would stay away from the CPR continuous overflow style though as it does and will lose prime and depends on an additional Aqualifter pump which is another point of failure at the worst possible moment. U tubes do not lose prime.
  9. AZDesertRat

    Replacing my RO/DI cartridges

    Always use 1 micron or smaller. I use a 0.2 micron absolute rated sediment filter and a 0.5 micron carbon block myself. The smaller the micron rating of the sediment filter the better it protects the pores in the carbon where the chlorine is adsorbed and the longer it will last. The better both work, the better they protect the RO membrane, the longer it lasts which in turn makes the DI last longer and work better. Lower cost of ownership.
  10. AZDesertRat

    Replacing my RO/DI cartridges

    Yes and no. It's as much about time and the possibility of bacteria and virus growth inside the housings which also leads to headloss and filter fouling as much as total gallons produced. Make sure you disinfect the system while you have it down too, this is important.
  11. AZDesertRat

    Replacing my RO/DI cartridges

    Sediment and carbon filters have nothing to do with TDS, their job is to protect the membrane from suspended solids, big stuff, and chlorine. TDS or dissolved solids are 0.0001 microns in size, sediment and carbon filters are 0.2, 0.5, 1 or up to 10 microns and larger, thousands of times to coarse to trap TDS. Yes, you replace the sediment and carbon filters every 6 months like clockwork unless you are using pressure gauges and a low range chlorine test kit to monitor for headloss and chlorine breakthru, then you MIGHT be able to extend that 6 months based on testing with them.
  12. AZDesertRat

    Hanna Checker for Chlorine Breakthrough

    I use the Hanna free chlorine tester in my water operations business for potable drinking water testing and have been pretty happy with it. The few things I will tell you is buy the calibration kit for it and check the calibration often and keep your glassware spotless. Even a little out of calibration when you are trying to test down in tenths of a ppm can be quite dramatic.
  13. AZDesertRat

    The Most Sensitive ATO available

    Spectrapure UPLC-II. It is completely adjustable from as little as 1/10" to 4" at the touch of a button. Multiple safety levels and it uses the same 3 roller peristaltic pump as their LiterMeter.
  14. AZDesertRat

    Why wont my rodi make water?

    Is that RO only TDS or RO/DI TDS? To troubleshoot you need 3 TDS readings, tap, RO only and final RO/DI. Also measure your waste ratio to make sure it is correct, too little waste and the membrane isn't being well flushed and too much waste and you don't have sufficient pressure available at the membrane for efficient treatment. Also what is your pressure gauge showing?