Today we are going to discuss RO/DI system basics, explain why almost every reefer uses
reverse osmosis deionized water and finish with a quick overview of what each stage of
a typical RO/DI system does.
Hi my name is Ryan and I am the host of BRStv where each week we explore a new topic related
to reefing.
This week we are going to dive into a piece of equipment that's found on basically every
long term successful reef tank out there, reverse osmosis deionization systems.
While this thing looks fairly complex with all the canisters, filters and tubes, it is
probably one of the easiest things you will ever install or use.
There are three hoses.
Attach one to your faucet, slide the waste like down the drain and the last one produces
ultra-pure water you can use with your reef tank.
If you feel like getting more advanced you can hook the system up permanently under your
sink, mount them on your wall or even set them up with a pressurized tank for purified
drinking water as well, all of these things we'll cover in detail within future episodes.
When you first decide to start a reef tank there are a few water options but most people
select tap water with some type of conditioner, reverse osmosis or deionized water.
While there are always exceptions to the rule, every reef tank I have seen that's been successful
for more than a few years uses RO or RO/DI.
As a new reefer most of us were just concerned about chlorine which is really simple to treat
with a water conditioner.
It's later on you start to learn the benefits of using a high quality source of water.
Recently one of our viewers posted a pretty insightful comment.
Reef keeping isn't about maintaining fish or corals, it's about maintaining water.
Best advice ever, healthy fish and corals are just a side benefit of being good at maintaining
pristine water.
First step of maintaining water is starting with high quality source water.
There are two main concerns with well and city water that go beyond simple chlorine.
First is it can contain nutrients like phosphate and nitrate which feed algae growth, slow
down calcification and resulting coral growth.
Fish food will almost always be the biggest source of these nutrients but maintaining
high quality low nutrient water should include a variety of efforts.
Second concern is general contaminants like metals and chemicals found in many water sources.
Farm run-off, old sewer systems, your homes copper piping, less than ideal water treatment
plants and 100 other things can all add unwanted contaminants to your home's water.
Because your tap water is mostly safe to drink it might seem safe for your tank but tap water
can contain elements that may not harm people but will irritate or kill more sensitive invertebrates
like corals.
However the more you learn about tap water the less you will want to drink it as well.
What your city or the EPA considers safe levels of disinfection bi-products, inorganic compounds
like copper, lead, arsenic, mercury and a laundry list of inorganic or organic compounds
might not be the same thing you personally want to consume, provide to your kids or pour
into a closed system like a reef tank where the levels consistently rise as water evaporates
and you add more of these elements each day.
While I realize my neighbors aren't dropping like flies from drinking the city water and
many tanks seem to do ok, especially in the short run.
Basically all of these items listed by the EPA as common water contaminants are known
to cause serious health related issues and can't be good for your corals either.
Rather than trust the safe levels they have come up with and your cities testing methods
I think just easier to buy an inexpensive RO system and remove as many of these things
as possible yourself.
No matter how you slice it reducing the sources of these things introduced to your body or
aquarium can't be anything but beneficial.
Reverse osmosis filtration will remove a vast majority of these things, many of them by
as much as 98%.
The second step of deionization can approach 100% removal with many common contaminants
and ideal for a reef tank.
Reverse osmosis water can be bought as most grocery stores, fish stores or made at home.
Grocery stores typically sell it out of a dispensing machine where you can fill your
own jugs.
This is often convenient and fairly affordable but you are at the mercy of how well the store
takes care of the machine.
Fish stores are often much better options because they know the importance of maintaining
their systems for reefing.
Fish stores also sell reverse osmosis deionized water which is what most reefers prefer.
Some of them even sell it premixed with salt.
Buying it at the fish store is sweet because it gives you a solid excuse to go look at
new fish and corals every couple weeks.
You can also purchase a RO/DI system for home use.
Honestly I think having ultra-pure water on demand at home for top off and water changes
are a cornerstone to success.
Fact is, having to go get water is an added step that makes water changes harder to do.
A solid water change schedule is probably the most closely related thing to long term
success and having a five year plus reef tank.
Time for a quick overview of how a system like this works.
This is what we call a five stage RO/DI system.
It has a single sediment filter, two carbon blocks, a RO membrane and the final stage
is the di resin cartridge.
The sediment filter is pretty much as it sounds a filter designed to capture sediment and
dirt so it doesn't clog the more expensive carbon blocks.
While these filters do all look the same they come in various qualities.
Using higher quality sediment filters will protect your other filters better, reduce
the replacement frequency and help maintain higher water pressures feeding the system
which will have a big impact on overall performance.
We recommend NSF certified GE Purtrex and RO.Z as some of the best options around for
sediment filters.
The next two are carbon blocks, they are typically installed in series with the one having a
larger micron size, often between 5 and 10, and the second one is often less than one
micron.
These filters are primarily for removing chlorine and volatile organic compounds like pesticides,
herbicides and hundreds of other man-made chemicals.
They will also remove unwanted tastes and odors.
We suggest looking for a brand that is made in the USA with US water quality standards
verses cheap imported versions and look for the NSF certified seal which means these filters
have been tested to insure their quality.
Our favorite has always been KX Technologies, they are pretty much the default leader in
the industry and what everyone else in the industry measures up to.
Some systems have a single carbon block rather than two.
In most cases a single block is suitable however dual blocks have some advantages.
First it provides longer contact time for more complete removal, second the smaller
micron carbon blocks are typically better at hard to remove volatile organic compounds
and running two blocks gives you a longer replacement window so it is less critical
to change them exactly on time.
The next stage is the RO membrane in the white container up top.
This is the filter that does a vast majority of the work, the rest of the filters were
more or less just prepping the water for the membrane.
A good functioning membrane will typically remove between 96 and 98% of the total dissolved
solids or TDS found in the water.
It is basically a thin membrane rolled up which allows water molecules to pass through
but rejects most contaminants and sends them out with the waste water.
If you maintain the pre-filters properly, this membrane can last as long as three years
or even longer.
Dow is a worldwide leader in RO membrane technology and really the undisputed king, in fact a
good portion of the other brands are just Dow material rolled at another plant.
The Dow 75 gallon per day membrane provides excellent performance at water pressures typical
in most homes and what we recommend in almost all cases.
There are 150 gallon per day membranes but they require higher pressures so you may need
a booster pump.
After the water leaves the RO membrane it is relatively pure and this is the type of
water most people would drink.
Most people don't drink deionized water because it is expensive, unneeded and arguably it's
not healthy to drink water this pure.
However for reefing needs we like to take it one step further with a final polish through
deionization resin.
This is because nutrients like phosphate an nitrate are some of the harder elements for
a RO membrane to remove so while the water has been substantially purified by the RO
system, there may be a disproportionately high level of these nutrients which the DI
resin will help further reduce.
DI resin is basically a bunch of negatively and positively charged beads which have an
affinity for many contaminants.
Once the water passes though the cartridge it should come out as zero TDS water and ready
for the tank.
In our industry it is fairly common to use a resin that contains a pH sensitive dye which
changes color and tells you when the resin is depleted.
One of the more common options changes from dark blue to a golden brown as it depletes.
The reason we don't use DI resin alone is because it only removes elements with an electrical
charge and in most cases it would be cost prohibitive.
It is much more cost effective to remove a vast majority of contaminants with the RO
system then use the DI resin for the final polish
If you have any questions or comments on this video, leave them in the comments area down
below, as always I look forward to interacting with all of you.
If this is your first time with us thanks for watching and be sure to give us a thumbs
up and subscribe.
See you all next week with another episode of BRStv.