OK since it looks like I have alot of evaporation in my tank I think I may ned to get an RO unit. Is this what most people use when they ned top off water? Not having aot of room or a place for a wall mount unit is there a portable one? One that can be hooked up like say a Python? Connect it get your water disconnect it and store it till next use?
RO Unit
- Thread starter taat2d
- Start date
I have an RO/DI that I just attach to a faucet and fill bucket(s). When I have enough water, I disconnect and place it back in the closet. If you have space and want to hard plumb it into your water system, you can but it's not necessary for any of the common systems I've seen. For protection, I use my bathroom sink and put it all in the tub. That way if I forget about it, I don't have to worry about a flood.
As to using it with a Python, I can't see how that would work. You could hook up to a large drum with a bottom drain, and feed tubing from there to your tank/sump for refill. A python could be used to siphon off the water and dump it down the drain, but you would still need separate siphon and refill tubes. I can't think of a way to make a python do double duty. I'd love it if there was, because my FW changes are much neater than my SW changes.
Henry
As to using it with a Python, I can't see how that would work. You could hook up to a large drum with a bottom drain, and feed tubing from there to your tank/sump for refill. A python could be used to siphon off the water and dump it down the drain, but you would still need separate siphon and refill tubes. I can't think of a way to make a python do double duty. I'd love it if there was, because my FW changes are much neater than my SW changes.
Henry
I'm not looking to use it with a Python. I was just asking if there is one to use the same way you use a Python. Which RO unit do you use? Is an RO unit something I really need? Or for top off water should I just treat tap water with a chemical?
Don't use tap water. You'll regret it for the life of your tank. RO/DI is a necessity, whether you buy a unit or pick up RO water from your LFS (test it yourself to be sure they are producing true 0 TDS water as some have been known to get lazy about servicing membranes/filters) or supposedly a local Walmart (they apparently have machines that dispense RO water, although I don't know of any Walmarts around here).
I picked up a pure-flo RO/DI on sale. The fact is, these units are all assembled pretty much the same way. The first canister is for mechanical filtration, followed by a carbon block canister (which is important in removing chlorine which will damage the RO membrane, along with other organics) then to the RO membrane, followed by, if you opt for it (I recommend you do) a DI cartridge. The output should have nothing in it, and show a reading of 0 TDS with a standard TDS meter.
The factors you need to consider are which membrane and what is the estimated output as gallons per day. Membranes rated for 50gpd and under are usually good for a 98-99% rejection rate, that is, not passing through 98% of minerals present through the membrane and rejecting that material into the waste water that is fed out on a separate line from the membrane canister. You can get higher gpd rated membranes if you need more water for a large tank, but rejection rates fall to 93-96%. Not true reverse osmosis, but more like nano filtration. However, the 4th stage DI canister will handle that slight excess, and you'll still end up with 0 TDS. You may run through the DI media faster, though, and need to replace the resin sooner. Still, it will give you the flow rate you need. The gold standard of membranes are DOW filmtecs', which are found on just about every decent system you'll find.
What does the expense and effort get you? Tap water is notorious for containing water treatments such as chlorine/chloramines for disinfection, although NYC water does not treat with chloramines anymore, just chlorine, and phosphates in the form of orthophosphates are added to water to "coat" pipes and reduce any leaching of lead from old lead soldered tubing, are the most common. Minerals picked up either flow through reservoirs or leaching into groundwater wells. This is why some water is regarded as "hard" and is characterized by difficulty in developing a lather from soap. Depending on the water source, nitrates may be present (the EPA allows up to 10 ppm of nitrate to be present and still be considered potable). It's pretty tough to work hard at reducing nitrates in your tank when your replacement water is starting at 10 ppm. Phosphates from other sources will also contaminate some water, leading to continuous attempts to remove phosphates from your tank to reduce algae blooms, and so on. These are some reasons why RO/DI water is needed.
In using RO/DI water for top off, you can take three approaches depending on your tank size. You can top off manually from a bucket with a measuring cup. You can buy an automatic top off controller which has a float switch, which, when lowered past a set point as evaporation occurs, activates a pump in a container to fill your sump/tank level back up to the float's off point. You can, if you are running a large tank, plumb your unit directly to your top off water container, and split off to a second container which you use to mix your SW.
Bottom line, you can set it up as simple as you want, or as automated as you desire. Still, it all starts with the same idea, purified water that can be your blank canvas to create the ideal water for your tank under your control. Your tap won't give that.
Henry
I picked up a pure-flo RO/DI on sale. The fact is, these units are all assembled pretty much the same way. The first canister is for mechanical filtration, followed by a carbon block canister (which is important in removing chlorine which will damage the RO membrane, along with other organics) then to the RO membrane, followed by, if you opt for it (I recommend you do) a DI cartridge. The output should have nothing in it, and show a reading of 0 TDS with a standard TDS meter.
The factors you need to consider are which membrane and what is the estimated output as gallons per day. Membranes rated for 50gpd and under are usually good for a 98-99% rejection rate, that is, not passing through 98% of minerals present through the membrane and rejecting that material into the waste water that is fed out on a separate line from the membrane canister. You can get higher gpd rated membranes if you need more water for a large tank, but rejection rates fall to 93-96%. Not true reverse osmosis, but more like nano filtration. However, the 4th stage DI canister will handle that slight excess, and you'll still end up with 0 TDS. You may run through the DI media faster, though, and need to replace the resin sooner. Still, it will give you the flow rate you need. The gold standard of membranes are DOW filmtecs', which are found on just about every decent system you'll find.
What does the expense and effort get you? Tap water is notorious for containing water treatments such as chlorine/chloramines for disinfection, although NYC water does not treat with chloramines anymore, just chlorine, and phosphates in the form of orthophosphates are added to water to "coat" pipes and reduce any leaching of lead from old lead soldered tubing, are the most common. Minerals picked up either flow through reservoirs or leaching into groundwater wells. This is why some water is regarded as "hard" and is characterized by difficulty in developing a lather from soap. Depending on the water source, nitrates may be present (the EPA allows up to 10 ppm of nitrate to be present and still be considered potable). It's pretty tough to work hard at reducing nitrates in your tank when your replacement water is starting at 10 ppm. Phosphates from other sources will also contaminate some water, leading to continuous attempts to remove phosphates from your tank to reduce algae blooms, and so on. These are some reasons why RO/DI water is needed.
In using RO/DI water for top off, you can take three approaches depending on your tank size. You can top off manually from a bucket with a measuring cup. You can buy an automatic top off controller which has a float switch, which, when lowered past a set point as evaporation occurs, activates a pump in a container to fill your sump/tank level back up to the float's off point. You can, if you are running a large tank, plumb your unit directly to your top off water container, and split off to a second container which you use to mix your SW.
Bottom line, you can set it up as simple as you want, or as automated as you desire. Still, it all starts with the same idea, purified water that can be your blank canvas to create the ideal water for your tank under your control. Your tap won't give that.
Henry
Last edited:
OK Henry. Thanx for all that info. I had to read it a few times and I still don't understand it totally. LOL Can you recommend a RO unit and a decent price? One more thing? Should I prepare water and leave it unsalted in a 5gal container and use that for my top off so I don't have to prepare water every day?
That's what I do. I fill a bucket and just scoop out of there to top off. You can find some nice units at a decent price at www.buckeyefieldsupply.com and www.airwaterice.com.
I like clear canisters to see the condition of the filters, especially the pre-filters, as well as the DI resin if it's a color changing product used to indicate remaining use. Still, a TDS meter is the most important tool. Once you see a rise in TDS, you'll know it's time for fresh DI resin.
BTW, my error up above. Dow does make a 75gpd rated true RO membrane. It's the >75 gpd membranes that have a slightly lower rejection rate.
I like clear canisters to see the condition of the filters, especially the pre-filters, as well as the DI resin if it's a color changing product used to indicate remaining use. Still, a TDS meter is the most important tool. Once you see a rise in TDS, you'll know it's time for fresh DI resin.
BTW, my error up above. Dow does make a 75gpd rated true RO membrane. It's the >75 gpd membranes that have a slightly lower rejection rate.
- Location
- Howell, NJ
Ebay is the way to go.. aquasafe rodi 6 stage filters are great... alot of us use it and we like em...
Anyone ever use these RO Units? Are they any good. I already spent WAY over my budget for my tank. I HOPE this is ok and I can save some money. BUT..... I also don't wanna buy it if it's garbage.
http://www.aquatictech.com/ro.html
http://www.aquatictech.com/ro.html
This is the unit I just ordered. It comes complete with a TDS monitor.
http://www.airwaterice.com/product/1COMPACT75
http://www.airwaterice.com/product/1COMPACT75
Buckeye Field Supply
Sponsor
- Location
- On the Internet
A suggestion:
First, unclip that DI cartridge from its clips, and orient the cartridge vertically with bottom up flow.
Although you may have saved a couple of pennies with the purchase, when you go to replace the sealed DI cartridge, you'll see they run about $20. Had you bought a full sized, vertical DI housing with a refillable cartridge, at refill time you'd only be out $12.
If you have trouble with production, and because you bought a system without a pressure gauge, you might want to either get a pressure gauge add on kit, or cobble one together from your local hardware store.
Russ @ BFS
Last edited:
The pressure gauge is to determine the water pressure from your plumbing feeding the unit. Low, or even oscillating pressure, will decease the amount of water processed per hour, as well as affect performance (their specifications call for a given minimum water pressure to meet their stated rejection rate). RO membranes requires enough pressure to to "push" solute across the filter to deliver your "purified" water.
Henry
Henry
Buckeye Field Supply
Sponsor
- Location
- On the Internet
Well said. In practical terms, if you've never had an RO system before, and you don't know what your line pressure is, you'd never know low pressure was the cause of your new system not working well.
During normal operation of an RO system, you use the pressure gauge to indicate when your prefilters are clogged.
Russ @ BFS
Depends on your water pressure, temperature, condition of pre-filters, as well as how "clean" your membrane is. You should back flush your membrane every month or so, depending on usage and ,to a degree, the TDS of your water source. To be rigorous in purification, a back flush for about 10 minutes would be done prior to each use. But, we're not making avian flu vaccine here, so flushing it every few months is fine.
Short answer, with a 75 gpd, you could get 5g done in a bit under 2 hours.
Henry
Short answer, with a 75 gpd, you could get 5g done in a bit under 2 hours.
Henry
Buckeye Field Supply
Sponsor
- Location
- On the Internet
Let me give you a little different take.
As Henry mentioned, production from these RO membranes are most affected by water pressure and water temperature. The factory specs for Filmtec membranes for example are 77 degree F water and 50 psi. Other brands of membranes typically are spec'ed at 60 or 65 psi. Colder water, or lower temps will slow production, resulting in less than 75 gpd from a 75 gpd membrane.
So, with factory spec conditions, a 75 gpd membrane will produce 3 gallons in an hour (75 gallons / 24 hours), and 5 gallons in 1.6 hours. Most people don't have 77 degree water, many people do have 50 psi.
Regarding "back flushing," remember that most point-of-use systems like those used in this hobby have no accommodation for flushing with a reversed water flow. Some systems have the plumbing in place to allow "flushing." There's no "back" about it.
Ideally membranes would be flushed as you turn the system OFF each time. That's not practical for most folks, so once a week is better than once a month is better than once a year.
Russ @ BFS
Buckeye Field Supply
Sponsor
- Location
- On the Internet
With factory spec conditions, a 75 gpd membrane will produce 3 gallons in an hour (75 gallons / 24 hours = 3 gph), and 5 gallons in 1.6 hours. Most people don't have 77 degree water, many people do have 50 psi. You production will likely be less than 5 gallons in 1.6 hours.
Russ @ BFS
How does the water get purified? I don't understand how it actually takes so long. Wha happens? The purified water drip out of the unit and into say a bucket while the rest of the water comes out a different end and runs into the drain?
Sponsor Reefs
We're a FREE website, and we exist because of hobbyists like YOU who help us run this community.
Click here to sponsor $10:
