I finally have moved and can no longer keep running back and forth to Trop for RODI water and actually have the space and everything else to get my own RODI unit. Figure I mix around 20-30 gallons of saltwater a week and go through about maybe another 10 with top off and dosing. I am looking for a reliable model and hopefully low waste water ratios. I know the ultra high efficiency models go for about 800+ which is more than I want to spend.
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RODI Unit Questions
- Thread starter mnat
- Start date
Mike, one of my interests is to go as green as I could with my tank. With this hobby, that’s difficult. I was told, and don’t know if it is true, that a 150 gpd RO unit (with dual 75gpd membranes) produces very little waste water. It supposedly runs the same water through both filters, cutting the waste (at least) in half. I haven’t looked into the truth of this, but it’s something I’d consider when I replace the one I have.
As far at which brand, I’m a bit pragmatic, and find they’re all the same as far as their plastic containers holding the membrane/filters. What’s important is the quality of the membrane and the filters you put into those plastic containers. With DI, I’ve converted an old three stage RO unit into a split bed unit (like a mini cati ani unit), so that regenerating the resin is a snap.
I like the four stage units…1 particle, 2 carbons and the membrane. The 75 gpd membranes have the best rejection rates…typically 98%. Would you happen to know your tds of your tapwater?
As far at which brand, I’m a bit pragmatic, and find they’re all the same as far as their plastic containers holding the membrane/filters. What’s important is the quality of the membrane and the filters you put into those plastic containers. With DI, I’ve converted an old three stage RO unit into a split bed unit (like a mini cati ani unit), so that regenerating the resin is a snap.
I like the four stage units…1 particle, 2 carbons and the membrane. The 75 gpd membranes have the best rejection rates…typically 98%. Would you happen to know your tds of your tapwater?
If i remember right.. Mikes City water was around 175 TDS.. The other thing too is to find out what the city PSI is coming into the home.. Most membranes 50+ GPH run better at 90 psi and you will have to buy a booster pump with Kit .. I got one from the last BRS group buy.. Even without the group buy BRS was the best deal around for the booster pump and kit
I can attest to Paul's statement. I originally had a 75 gpd unit from TB Aquatics. Waste water was about 3 buckets to 1 bucket of RODI. I later added a 75GPD upgrade kit from Bulk Reef Supply, and after that my waste water went down to a little more than 1 bucket of waste to 1 bucket of RODI. That was a significant improvement and I'm sorry I didn't get that from the beginning. Not only did it save water, but it also saved time too.
The way it works is the extra DI filter got added so the waste line of the first one goes into the 2nd DI filter, and then the DI outputs of both get connected with a "wye" fitting. It's basically like having two RODI units working at the same time, but the carbon and sediment filtration is done once for both DI membranes.
I highly recommend this type of setup. In fact, if you got involved in that one BRS group buy, you should get preferred pricing, so here's what I suggest:
Go To BRS for "Build your own" and select the following options from the drop down boxes...
Stage One - 1 Micron Sed Filter
Stage Two - 1 Micron Carbon Block (or get the Chlorplus if you think your tap water has a lot of chlorine)
Stage Three - None (or you can add an extra Carbon Block, I don't think it's necessary)
Stage Four - Water Saver 150 GPD Upgrade (Uses 2 75 GPD Membranes)
Stage Five - None (Not sure if you can add a third DI membrane... but that might be more efficient)
Accessories
- Dual TDS Meter (Gives readings on TDS after the sed/carbon filters... which is before the DI membranes, and then after the DI membrane(s). If you keep track of the IN/OUT readings, you will be able to tell when you need to change the sed/carbon filters and the membranes, respectively.
- Depending on where you will connect it, you will need either the garden hose adapter or the faucet diverter, or just the self-piercing valve to get flow into the RODI.
With all of that, my preferred pricing is about $175 (using the garden hose adapter). That's basically the system I have now, and I have about 5 TDS going into my DI membranes, 0 TDS coming out.
You can also optionally add a float valve and auto shutoff valve for $15 more (total for both), and/or a ball valve for $5 more. You will need some kind of valve to control the flow, be it manual operation or automatic (shutoff/float).
Also, not sure if that "build your own" would come with any tubing, so you'll probably need to get some of that too. Call them up before placing the order to ask. If it's not included... Tubing is fairly cheap. You can buy it by the foot at BRS too.
Hope that helps Mike.
The way it works is the extra DI filter got added so the waste line of the first one goes into the 2nd DI filter, and then the DI outputs of both get connected with a "wye" fitting. It's basically like having two RODI units working at the same time, but the carbon and sediment filtration is done once for both DI membranes.
I highly recommend this type of setup. In fact, if you got involved in that one BRS group buy, you should get preferred pricing, so here's what I suggest:
Go To BRS for "Build your own" and select the following options from the drop down boxes...
Stage One - 1 Micron Sed Filter
Stage Two - 1 Micron Carbon Block (or get the Chlorplus if you think your tap water has a lot of chlorine)
Stage Three - None (or you can add an extra Carbon Block, I don't think it's necessary)
Stage Four - Water Saver 150 GPD Upgrade (Uses 2 75 GPD Membranes)
Stage Five - None (Not sure if you can add a third DI membrane... but that might be more efficient)
Accessories
- Dual TDS Meter (Gives readings on TDS after the sed/carbon filters... which is before the DI membranes, and then after the DI membrane(s). If you keep track of the IN/OUT readings, you will be able to tell when you need to change the sed/carbon filters and the membranes, respectively.
- Depending on where you will connect it, you will need either the garden hose adapter or the faucet diverter, or just the self-piercing valve to get flow into the RODI.
With all of that, my preferred pricing is about $175 (using the garden hose adapter). That's basically the system I have now, and I have about 5 TDS going into my DI membranes, 0 TDS coming out.
You can also optionally add a float valve and auto shutoff valve for $15 more (total for both), and/or a ball valve for $5 more. You will need some kind of valve to control the flow, be it manual operation or automatic (shutoff/float).
Also, not sure if that "build your own" would come with any tubing, so you'll probably need to get some of that too. Call them up before placing the order to ask. If it's not included... Tubing is fairly cheap. You can buy it by the foot at BRS too.
Hope that helps Mike.
Is it possible that output of RODI unit has more TDS than input ? I think I have it.
Also it seems that water flows thru (good and bad) too much.
When the system was new, output was fairly slow.
I have GE RODI system (from Home Depot) with 3 gal container. It used to work fine, but now (even after replacing all filters (1 carbon prefilter, 1 blue membrane, 1 post filter) flow is too much and most into 'waste'. ???
Also it seems that water flows thru (good and bad) too much.
When the system was new, output was fairly slow.
I have GE RODI system (from Home Depot) with 3 gal container. It used to work fine, but now (even after replacing all filters (1 carbon prefilter, 1 blue membrane, 1 post filter) flow is too much and most into 'waste'. ???
The output shouldn't have more TDS than the input. Assuming you are using a dual TDS meter, you may have the sensors connected to the wrong tubes.
Can you post a pic of your RODI unit and try to describe the direction of flow?
If your flow is running faster than it used to, it could be due to increased pressure from the water company. They sell restrictors to reduce the flow rate and they are simple to install. They just slip inside the end of the tube that connects to the rodi unit.
Can you post a pic of your RODI unit and try to describe the direction of flow?
If your flow is running faster than it used to, it could be due to increased pressure from the water company. They sell restrictors to reduce the flow rate and they are simple to install. They just slip inside the end of the tube that connects to the rodi unit.
i use this one: $150
http://www.airwaterice.com/c=lxVRC9...N/Typhoon-5-stage-RODI-Reefkeeper-75-GPD.html
but i think (i could be wrong), i heard someone (taz?) say the replacement filters from them weren't working right. My replacement filters worked great - so no complaints here.
http://www.airwaterice.com/c=lxVRC9...N/Typhoon-5-stage-RODI-Reefkeeper-75-GPD.html
but i think (i could be wrong), i heard someone (taz?) say the replacement filters from them weren't working right. My replacement filters worked great - so no complaints here.
A few of us had probs with replacement filters.. Some had DI issues like me( stuff was almost spent before use) and some had membrane issues