Water changes are done to remove nitrates and impurities
from the aquarium water. High nitrates indicate an aquarium in need of more
frequent water changes. Water changes is where the reverse osmosis water comes into use.
WHAT IS REVERSE OSMOSIS?
Reverse Osmosis is a method of filtering water by
pressing the water against a semi-permeable membrane that sits inside a filter
housing. This membrane allows water molecules to pass through, but not others.
Minerals, trace and other elements are removed producing pure raw water. This
water is too pure for aquaria use without reconstituting. Marine hobbyists add
salt mixes containing all the essentials. Soft water aquarists must also add
trace elements and minerals back to the water to make it suitable. Pure ro water is not suitable for discus fish or angel fish.
HOW DOES THE RO FILTER WORK? Reverse Osmosis Filter Basics:
The water passes through several filters, each
representing a stage.
STAGE ONE : Water enters the filter through a micron sediment prefilter. This removes small particulates, bacteria, cysts, spores and grains of
STAGE TWO : The water then passes into the
carbon prefilter. This removes chlorine, toxins and chemical impurities along
with any pipe cleaning additives used by the water department. It is crucial
that a high quality carbon block is used for this stage. The best carbon blocks
available today are capable of removing chloramines, a mix of chlorine and
ammonia that many municipal water suppliers now use as disinfecting agents in
tap water supplies. A reverse osmosis filter is only as good as the components
making up the system. Osmotic reverse osmosis filters use the highest quality
STAGE THREE :
Next the water passes through
the membrane to complete the filtering process. There are numerous grades and types of membranes available.
membranes are thin film composite. They are suitable for well water or city tap water.
Chlorine can damage them but a good carbon prefilter solves this. In the past
distinctions were made on membrane application based upon whether it was to be
used on a chlorinated tap supply or untreated well water. CTA membranes,
cellulose triacetate, can handle chlorine but they are more costly, less
efficient and not necessary. The vast improvement in carbon block quality will
render these obsolete. The best membranes on the market are tested and certified
by the NSF and approved by the FDA for drinking and food use. They feature
high removal rates of silicates, phosphates, nitrates and other compounds.
Contaminates removed by the filter are discarded through tubing going into a
drain. The "reject" brine water used in this is the equivalent of taking a
couple extra showers per week or washing the car. The reject water is not
similar to turning on a faucet. It is a small stream going through 1/4" tubing.
ro is much easier to use and more economical than the other two methods of
water purification which are deionization and distillation. ro water can be
"polished" with di as an extra stage after the ro. for sensitive reefs
requiring totally pure water. In this case the di filter is not quickly
exhausted as the ro membrane has done most of the work. Pure product water (ro
water) is delivered through tubing coming from the membrane. It drips out at a
rate determined by the size membrane. A 50 GPD ro filter will produce close to 2
gallons per hour under ideal conditions. Performance is based upon water
pressure, supply water temperature and system design. Osmotic reverse osmosis filters are designed for
high efficiency. In low pressure situations a booster pump
is used to increase pressure. The ro tubing coming from the membrane can be
attached to a float in a sump or barrel, to the ice maker on the fridge, to a
drinking water tank or any combination. An auto shutoff valve is used in this.
You can tee off to as many devices as desired. However this must be configured
properly. When adding floats on a drinking water system special considerations
arise which must be addressed properly including the addition of a a check valve
to prevent back flow from the barrel. When using a float, the auto shutoff valve
must be used to prevent harmful back pressure on the membrane. Without a shutoff
valve the filter must be manually turned on and off for each use by turning on
the cold water supply.
ADDITIONAL STAGES :
The ro filter may
have a di filter on it, which is another stage. This is referred to as an rodi filter. Some have multiple carbon
prefilters which represent more stages. With the new improved technology of the
manufacturing processes, the best carbon blocks today remove all components of
chloramines, which was unheard of just a few years ago. Osmotic ro filters use the highest
grade of carbon block available today. All municipal water
supply companies will be using chloramines if they are not already using them.
Chloramines are chlorine and ammonia used together to disinfect the tap water.
Some generic brand ro filters add unnecessary extra stages as a selling point to sound impressive and boost refill cartridge sales.
REVERSE OSMOSIS RO FILTER OPERATION
First step-The filter is attached to the tap
water supply. Most ro units feature a diverter that will attach to any
sink in any house. Osmotic reverse osmosis filters easily attach to any sink in the house.
To operate the filter, you turn on the cold water and
pull a small lever on the diverter. This sends the tap water to the unit. Simply
turn off the water to stop the operation. There are several options for
attaching the tap water supply to the filter. A garden hose fitting or saddle
valve may be used.
Second step- Place the brine reject tubing
into the sink drain. This carries impurities down the drain. If attaching the
filter to a saddle valve on the cold water supply, the brine reject line can
also be attached to a saddle valve on the drain line.
Third step-Place the ro product tubing
into a barrel or container to hold the water. If using an auto shut off
valve, attach the float at this time.
Finally, after all tubing is attached properly, turn on the cold
water supply. This places the filter in operation. The efficiency is determined
by the temperature of the water and the pressure of the supply water. Cold water
only should be used on the filter.
Because the reverse osmosis filter is rated in output gallons per day (24
hour period) , water does not pour out of the filter. The ro water is produced
in a slow, steady dripping stream. Pressure is usually not a problem on city
water supplies. ro membranes require a minimum of 60 pounds of supply water
pressure to operate at rated efficiency. On well systems there is a simple
device to boost pressure on the filter. There are many ways to install your
unit. It easily fits under the sink when used as a drinking water filter. The
supply of tap water can be fed with a self piercing saddle valve or a valve that
goes in line on the existing cold water shut off valve valve for the faucet. A
saddle valve is also available for the drain line. The product tubing can run up
or down, quite a distance to any location. When the auto shut off valve senses a
demand it places the ro filter in use. When the float closes the water flow,
the shut off valve turns off the filter.
IS THE AUTO SHUT OFF VALVE STANDARD EQUIPMENT ON RO FILTERS?
No. Auto shut off valves are always on complete drinking water systems. They are not a component found on most ro filters but are sold as accessories. Many hobbyist order ro filter units from mail order companies that refer them to the manufacturer for the add on options. Installing the auto shut off valve on the ro filter involves
cutting all tubing and installing the valve in a precise configuration. Any time
ro water is stored in a barrel, these components are necessary. For this
reason, we offer a line of ro filters with these features preinstalled.
For details on the barrel storage kit:
RO Filter Sales
SHOULD THE MEMBRANE BE BACK FLUSHED?
Yes. When the ro filter is used strictly for drinking water a
light demand is placed on the membrane. For instance a 50 GPD membrane will
easily keep a standard 3 to 5 gallon drinking water storage tank topped
off as water is used. However, when the ro filter is used for other
applications and larger storage barrels are filled and frequently depleted of water, the membrane
is placed under a heavy demand. In this case it is advisable to back flush the ro
membrane on a regular basis. This simply involves opening a valve for 3 to 5
minutes to flush accumulated mineral deposits off of the membrane. Remember,
water is pressed against the ro membrane and pure water passes through while solids
(minerals) are eliminated by the brine reject line. With time, suspended and
precipitated solids accumulate on the membrane. This reduces membrane
efficiency. Back flushing removes much of this deposit. This will ensure optimum
life for your membrane. Osmotic ro filters have this feature as standard equipment.
Most ro filters sell this
as an add on option. To add a membrane back flush valve to your existing ro
filter for $15. :
HOW OFTEN MUST COMPONENTS BE REPLACED?
This varies depending upon demand and water conditions.
a rule of thumb, the sediment prefilter cartridge should be replaced every 4
months. The sediment filter works from the inside to the outside. When
discoloration is visible it is time to replace it. Some ro filters feature a uv resistant clear sump housing which allows cartridge condition to be checked
at a glance. The carbon block prefilter should be replaced every 6 months.
Keeping the sediment filter clean protects the carbon block from clogging. As
filters become exhausted, system efficiency and ro water output declines. The
membrane replacement schedule is variable. On a drinking water filter the
average life is three years. On a system used in aquaria the time is shorter due
to the higher usage. Membrane life can be prolonged by using a membrane back flush
valve. This is explained in the paragraph above. If filter output sharply
declines even with new prefilter cartridges, it is time for a membrane
replacement. The harder the water in your area the faster a membrane is
exhausted. The condition of the membrane can be tested with an electronic pen
tester. As the membrane becomes exhausted, the TDS (total dissolved solids)
will rise. It is normal for ro water to have some change in ph as tap water
can vary in ph and changes dramatically twice a year in many areas.
CAN I UPGRADE MY EXISTING RO FILTER TO A HIGHER OUTPUT?
Yes. The 100 GPD membrane will fit your existing ro
filter membrane housing. It is physically the same diameter as the smaller
membrane but is much denser. You can upgrade your ro filter as easily as changing the membrane and flow restrictor
fitting. The flow restrictor meters the flow to match the membrane. A 100 GPD
membrane is only a few dollars more than a 50 GPD membrane. A 150 GPD
membrane will fit your standard housing. For details:
150 gpd ro membrane
SHOULD A DI FILTER BE USED WITH THE RO FILTER?
The rodi filter provides the purest water possible
for aquarium use. Reef and marine
aquaria require pure water. For discus and soft water fish it is not
necessary but some choose to use it and then reconstitute to the desired
parameters. To purchase a di filter to add to any ro filter or di refill
cartridge visit our ro filter sales page.
HOW SHOULD RO WATER BE USED IN AQUARIA?
RO water should be used whenever soft pure water is desired. In marine and reef aquaria, the ro water is blended with salt mixes appropriate for the intended use. This adds trace elements, salts and
minerals necessary to maintain life. Using pure water eliminates the
cause of many unsightly problems encountered with tap water.
Impurities, including phosphates, nitrates and silicates are removed.
Many of these impurities provide nourishment for undesirable bacteria,
algae forms and other undesirables. For discus and other soft water
fish, the ro water is reconstituted. This means adding the trace
elements and minerals back into the water. For discus breeding, the
water can be reconstituted using commercial products until the desired
hardness is achieved. Tap water that has been purified by carbon
filtration can be used to reconstitute the ro water. The filtered
tap water is carefully blended with the ro until the correct
hardness is achieved. This will give you softer water with a proper ph
level. This method is fine for growing and maintaining discus. You can
use a measuring cup to determine the ratio of tap to mix with ro. It
is not necessary to blend the ro water and tap water in a barrel. When changing water, you can add the proper amount of ro water to
the tank followed by the tap. If the tap is unfiltered a
dechlorinating agent must be used. These contain salts and often
buffers are added to them which can alter the water chemistry,
possibly defeating the purpose of using ro. Use care in choosing
which dechlorinating product to use. The obvious choice is to remove
chlorine and harmful substances from the tap water by carbon
filtration. Python type refill tubing can be plugged directly into the
carbon filter and used at temps suitable for discus. Tap water filters
are inexpensive and remove major impurities from the water including
disinfecting agents such as chlorine. Care must be used to select one
that is rated for warm water.
RO water should be stored in a food grade drum, large size ro
drinking water tank or large water container approved as food grade.
Food grade barrels are a little more expensive than trash cans or
other containers, which may have various chemicals including mildew
retardants added to them during manufacture. Garden hose is unsafe due
to the chemicals used in many of them. Some may be okay but it is a
risk not worth taking. Clear poly tubing is good for moving water. The
storage container should have constant aeration. Heat should be
On a regular basis the storage barrel should be cleaned. This should also be done to canister housings when replacing cartridges. To clean filter housings scrub well with a weak vinegar solution followed by rinsing.
should not be added to the ro storage barrel. Dechlorinating products should not be
added to the barrel. You do not want the nitrification process
starting in the storage vessel as the water could then contain
ammonia, nitrites or nitrates. When using the blend method, pump the
ro into the aquarium followed by the tap. A pump with tubing (simple aquarium submersible powerhead pump) is used
to deliver the water from the storage barrel to the aquarium. Never
use a garden hose. Use clear poly tube. The clear tubing can easily be
cleaned periodically by submersing for a few hours in a 5 gallon
bucket with hydrogen peroxide. This can also be used to clean the
barrel. Attach a small powerhead to the tubing to circulate the
water through the tube. Drain and rinse well. In the past, 100
GPD membranes were large and bulky and did not fit standard size
housings. Due largely to demand from aquarist use, manufacturers now
make higher capacity membranes that easily fit standard size housings.
In the past, a 100 GPD filter involved stacking two 50 GPD membranes
into "piggyback" fashion. When membrane replacement time rolled around
you had to obtain two membranes. The recent advances in component
manufacture make ro filtration an economical solution to water
purification for aquarists. With all municipal water supplies
switching from chlorine to chloramines (ammonia and chlorine) as the
disinfecting agent in tap water, carbon block manufacturers have
designed filters to remove chloramines. I hope this has given you some insight
into the area of using ro filtration in the discus fish aquarium and any aquarium application requiring soft, pure water.
Copyright 2001; Revised October 2005 by Al Johnson,
author. Al spent many years working as a plumber with specialized training and state certification in back flow prevention device installation, testing, repair.
|PayPal service provides fast, easy, and secure payments for your online purchases with Rocky Mountain Discus! You are not required to open a PayPal account to use our online shopping. Order by phone for conventional credit card or debit card processing.|
Discus Fish Care |
Food and Medications |
Water Filtration |
Customer Gallery |
Site Map |
Email Us |
© Copyright Rocky
Mountain Discus, All Rights Reserved