Loading... Please wait...

FAQ

When should I replace my filters?

Will Buckeye filters fit properly in my water filtration system?

Do I need to do anything special when I install new cartridges in my RO or RO/DI system?

Is there a right way and a wrong way to load a refillable cartridge with replacement DI resin?

What's the difference between color-changing DI resin and non color-changing resin?

Some RO and RO/DI units come with a pressure gauge, and other don't. Is a pressure gauge a feature I should be interested in?

I want to increase the output of my RO system - can I replace my exiting RO membrane with a higher capacity membrane?

Why are filters sometimes described in terms of “microns?"

How do I remove tubing from a quick connect fitting?

Are horizontal DI housings OK?

I want to purchase a Buckeye RO/DI system. Are there any other parts I need to get the system up and running?

How much water pressure is needed to run an RO or RODI system?

When should I replace my filters?

A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the usable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or more of the prefilters (all the filters that touch the water before it reaches the RO membrane) is beginning to clog.

Also be cognizant of the chlorine capacity of the carbon block. A good 0.5 micron carbon block for example will remove much of the chlorine from 20,000 gallons of tap water presented at 1 gpm. Some original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons. Remember that all the water you process, both waste water and purified water, goes through the carbon block.

Regarding your RO membrane and DI resin, use your total dissolved solids (TDS) meter to measure, record, and track the TDS (expressed in parts per million [ppm]) in three places: 1) tap water, 2) after the RO but before the DI, and 3) after the DI.

The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 ppm. Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?

If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO membrane housing and you'll see it is still approximately 400 ppm.

The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 96% (i.e., they reject 96% of the dissolved solids in the feed water). So the purified water coming from your 100 gpd membrane would be about 16 ppm (a 96% reduction). Filmtec 75 gpd (and below) membranes produce purified water (a.k.a. “permeate”) more slowly, but have a higher rejection rate (96 to 99%). The lifespan of an RO membrane is dependent upon how much water you run through it, and how “dirty” the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the TDS in the water coming into the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce purified water more slowly as their function declines.

After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the TDS in the RO water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm, your resin needs to be replaced. Sometimes you'll hear people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin high TDS water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal.

Additionally, don’t forget to sanitize the entire system at least once per year, and wash and lube your housing o-rings with food-grade silicone grease every filter change.

Will Buckeye filters fit properly in my water filtration system?

We hear this question frequently – and with good cause. There is typically little if any information provided by original equipment suppliers in this regard. Fortunately this is an easy riddle to solve for purification system owners! Filter cartridges (e.g., sediment filters, carbon block filters, GAC cartridges, DI resin cartridges), and therefore the internal dimensions of the housings that contain them, come in only a few standard sizes. The sizes are very different from each other, so you don’t have to worry about making precise measurements of your housings.

Housings are typically designed to accommodate filters of one of the four following dimensions:

  • 2.5 inch diameter x 10 inch length
  • 4.5 inch diameter x 10 inch length
  • 2.5 inch diameter x 20 inch length
  • 4.5 inch diameter x 20 inch length

 Nearly all residential RO and RO/DI systems used in the marine aquarium hobby are designed to utilize 2.5 inch diameter x 10 inch length filters. Now – one note just to complicate things – you’ll sometimes see filters for these housings that measure 9 ¾ inch or 9 7/8 inch in length – no problem! They will fit just fine in standard 10 inch housings.

Also note that there are filters with dimensions other than those listed here, but there is a very high likelihood your system uses the 2.5 inch x 10 inch filters.

Do I need to do anything special when I install new cartridges in my RO or RO/DI system?

 Well, yes and no. New sediment filters can simply be installed, and you're done. As for carbon blocks, RO membranes, and DI resin, that's another story...

Manufacturers recommend flushing new carbon block cartridges for at least 10 minutes before using the product water. Don’t run flush water through other stages in your system.

If you are using Catalytic GAC, or CGAC to treat chloramines, it is critical that you thoroughly rinse these cartridges. They will release fine black carbon dust when first installed. Don’t run this rinse water through later filter stages.

Manufacturers recommend flushing new RO membranes for up to 40 minutes to remove preservatives before using the product water. Don’t run flush water through other stages in your system.

Run 1.5 gallons of flush water through new DI resin before using the product water. Avoid contaminating (e.g., bacteria/mold/fungus) DI resin. Minimize storage time. Store DI resin in an airtight container to keep it moist until use. Store unused DI resin in an opaque container to avoid exposure to light. Clear shipping bags are appropriate for long term storage. Treat your resin gently! If resin is exposed to freezing temperatures during shipping, allow it to warm at room temperature for 24 hours prior to use.

 Is there a right way and a wrong way to load a refillable cartridge with replacement DI resin?

 Yes! Seems like this would be a simple matter of unscrewing the bottom of the cartridge, dumping the old resin in the trash, placing fresh resin in the cartridge, and replacing the cartridge in the housing. Well, almost...

 It's how you place the new resin in the cartridge that's important here. First a little background on DI resins.

Perhaps the most common ion exchange resin used in the production of ultrapure water is “mixed bed resin.” This resin is composed of a mix of small plastic cation beads and anion beads that remove positively charged, and negatively charged ions, respectively. These beads work most effectively when they are thoroughly mixed (which is the way they are when you buy them).

To assure the beads stay mixed together, pack the beads tightly in the refillable cartridge. Fill the cartridge to within a 1/4 inch of full with resin. Now pack the resin by dropping the cartridge repeatedly (~15 times), rubber washer end down, on a hard surface from a height of about 1/2 inch. Essentially what you are doing is bouncing the cartridge to get the resin to settle. You'll see the resin settle significantly. Add more resin and settle it again. You'll not see as much settling this time. Now fill the cartridge a third time to within 1/8 inch of the top and pack the resin a third time. If you see any settling at all, refill to within 1/8 inch of the top, replace the cap, and you're good to go! Packed in this way, you'll not see the resin separate over time.

Lastly, make sure the resin cartridge is placed back in the housing with the rubber washer end up.

What's the difference between color-changing DI resin and non color-changing resin?

The inclusion of a water-soluble indicator in color-changing resin yields a color change as a general indicator when the resin is exhausted. We carry both color indicating (i.e., color-changing) resin, and non color indicating resin. They are identical resins except for the indicator. Use the color-change feature as a very general indicator only. You can commonly continue to use the resin for weeks or months after it begins to change color. Use a TDS meter to monitor how well the resin is performing, and when it’s time for a new resin refill. If you have a TDS meter, we recommend the non color-indicating resin. The indicator in color-indicating resin can be measured in minute quantities (parts per billion) in product water. There are no known harmful effects of the indicator, but why not avoid it if possible.

Some RO and RO/DI units that come with a pressure gauge, and other don't. Is a pressure gauge a feature I should be interested in?

Typically, pressure gauges are installed in RO and RO/DI systems so that they read the water pressure in the system after the prefilters and before the RO membrane.

This provides some very useful information. First, it will tell you if your home's water pressure is sufficient (or in rare cases too high) for an RO system. In unusual cases the pressure is not high enough and a booster pump will be required. The problems caused by low water pressure may be exacerbated by cold tap water temperature (during winter months, for example).

So you've hooked up your new system, and your pressure gauge indicates you have sufficient water pressure (sometimes referred to as “line pressure”). What good is a pressure gauge to you now?

If you record the line pressure with new sediment and carbon filters, a reduction in line pressure will be an indication that one or more of the prefilters is clogged and need to be replaced.

So, as a TDS meter allows you to monitor the function of the RO membrane and the DI resin, a pressure gauge allows you to monitor water flow through the prefilters.

Buckeye's Premium Series units come complete with a pressure gauge. We also sell add-on pressure gauge kits that are very easy to install.

I want to increase the output of my RO system - can I replace my exiting RO membrane with a higher capacity membrane?

 Assuming your system accepts stand-sized membranes, you can add a higher (or lower) capacity membrane very easily. Pull the old one out, slip a new one in, and flush the new membrane appropriately. You'll also need to replace your flow restrictor. Flow restrictors are matched to the capacity of the membrane, and serve to partially plug the waste line that exits the RO housing. By partially blocking flow in the waste line, flow restrictors serve to pressurize the RO housing. It’s this pressure that allows the reverse osmosis process to work. All RO systems have flow restrictors.

There are three general types of flow restrictors. The plug-type restrictors are just that - a small plastic cap, or plug with a very small hole that is inserted in the waste line of the RO (sometimes these come inside the fitting in the waste port of the RO). To find this type of restrictor, remove the waste line from the waste port on the RO housing, and look INSIDE the tubing. Remove the restrictor and replace it with a restrictor sized appropriately for your new membrane.

Some systems use a capillary flow restrictor. These restrictors look similar to the plug type, except they have a long (several inches to a foot or so), thin capillary tube extending from the cap. Again - this type of flow restrictor can be found inside the waste tubing.

A third type, sometimes called cartridge, block, or tube restrictors, look like a short length of 1/2–inch pvc tubing with a quick connect fitting on each end. Some of these restrictors have an integrated flush valve.

Why are filters sometimes described in terms of “microns?”

Manufacturers commonly describe the size of the pores in filters, and therefore the maximum size particle that will flow through a filter in terms of microns. A micron is 1/1,000,000th of a meter or approximately 0.00004 inches. The smaller the micron rating, the smaller the particles the filter will catch. Unfortunately, manufacturers rate filters based upon this pore size without applying a standard technique to express the ratings. Some manufacturers/retailers claim filter ratings expressed using nominal numbers. Others claim filter ratings using absolute numbers. Some round off one or the other ratings. Many (most) don't tell you which rating system they are claiming. For example, a 5 micron absolute filter removes a very high percentage (approaching 100.0%) of particles 5 microns or larger; while a 5 micron nominal filter will remove approximately 85% of particles 5 microns or larger.

How do I remove tubing from a quick connect fitting?

This is an easy one, but it is a question we hear from time to time. Push the ring on the fitting (the collet) in towards the fitting and pull the tubing out. If the tubing doesn’t come out easily, it’s likely the collet isn’t pushed all the way in, and/or there is pressure inside the fitting and tubing. Release the pressure by bleeding it off from somewhere else in the system, push the collet in all the way, and the tubing will come out easily.

Are horizontal DI housings OK?

Horizontal DI housings are a design intended to minimize the original cost of the system - you should be prepared for the tradeoffs. Horizontal DI units typically contain 8 oz. to 16 oz. of resin. Typical 10” x 2.5” vertical DI cartridges contain 20 oz of resin. Obviously the more resin contained in the housing the longer it will last and the better treatment it will provide.

Some horizontal DI housings are not refillable - you'll therefore have to pay for a new housing every time you need to replace the DI resin. The cost of repeatedly replacing the horizontal housing will far outweigh any money saved up-front in purchasing the unit.

Perhaps most importantly, horizontal DI housings are a less than ideal arrangement for water treatment. DI resin beds shrink/settle through normal use over their life span. You'll note that a cartridge that was full when new can sometimes have a ¼ inch of empty space in it when fully expended. When DI resin settles in a horizontal housing, it leaves a pathway (of least resistance) along the top of the housing where water can flow while coming into minimal contact with the DI resin.

You’ll note that the output from the DI housing is at the center of the end of the housing. Depending upon how your system is configured, RO water may enter the DI housing in port, fill up the housing until the water level reaches the out port (i.e., fill up the bottom half of housing), and then exit the DI housing. Your RO water has been in contact only with half the resin in the housing.

How do I know a good carbon block cartridge when I see one?

For purposes of the marine aquarium hobby, consider two items: pore size and chlorine capacity. The smaller the pore size, the greater protection the block offers your RO membrane. Carbon block cartridges with a pore size of 1 micron to 10 microns are common. Carbon blocks with smaller pore sizes serve as a backup filter to catch those few particles that make it past the sediment filter. For example, the Chlorine Grabber has a nominal rating or 0.5 microns, and an absolute rating of 2 microns. You'll also see it rated at a 1 micron (0.5 micron rounded off). Because a sediment cartridge should be in line ahead of the carbon block, the primary purpose of the carbon cartridge is to remove VOCs - volatile organic compounds, and more specifically in filtration of tap water, what we really want it to do is remove chlorine.

Use a sediment filter ahead of any carbon block. The pore size on the carbon block should be about equal to, or larger than the sediment filter pore size.

Just how much chlorine will a carbon cartridge remove? The cartridges are rated in terms of chlorine capacity. The Grabber for example will remove >90% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.

I want to purchase a Buckeye RO/DI system. Are there any other parts I need to get the system up and running?

 First, you’ll need a way to tap into your home’s plumbing in order to supply water to the system. There are many ways to do this – some require advanced DIY skills like cutting and soldering copper pipe and fittings, while others are very straightforward. For those comfortable with cutting and/or soldering copper pipe, a visit to a good hardware store will yield any number of different fittings and valves to go from ½ inch copper pipe to ¼ inch tubing. Buckeye offers a number of other options to connect to a faucet, to a garden hose bib, and under a sink at the cold water shut off valve.

Some general advice about measuring TDS

Total Dissolved Solids are measured in parts per million, or "ppm." When using an RODI system, we often try to measure TDS down near 0 ppm. Because this TDS level is so low, we have to keep in mind the sensitivity of the meter used to measure it, and the technique used to measure the tds. 

Nearly any contamination in the sample container will cause an erroneous TDS measurement. Some plastic containers are difficult to get absolutely clean, and although they appear clean, they are not. An easy standard approach is to use a drinking glass as a sample container - use one right out of the dishwasher. Obviously, keep your fingers away from the inside surface of the glass.

Calibrate your meter. Use a calibration fluid generally in the range of the tds measurements you'll be taking. Some meters require a specific tds calibration fluid (e.g., 800 ppm), regardless of the tds levels in your samples.

Be careful with how you take your samples. Let's say you intend to measure the TDS in your 1) DI water, 2) RO water, and 3) tap water. Start with the cleanest of the three - the DI water. After letting the system run for a sufficient period of time that you are sure the tds levels have stabilized (to assure you are not measuring “TDS creep” water), rinse the sample container two or three times with the water you intend to sample, and then fill the sample container with sufficient DI water to take a reading.

Now on to the RO water. The water we are interested in here is the permeate – i.e., the water that has been purified by the RO membrane – not the waste water. Make sure you understand which is which before taking the sample. You may need to unhook some tubing to take this sample. This is inconvenient for many people, and we find that people never do it.  They report only the tap water TDS and the DI water TDS. Contact Buckeye if you need guidance regarding installing a couple of extra fittings and tubing to facilitate measuring the TDS of the RO water (permeate). When you take the sample, follow the same procedure described above – use a clean sample container, assure you are not measuring TDS creep water, and rinse with the permeate several times before taking the sample.

Use the same approach to collect and measure your tap water as well.

How much water pressure is needed to run an RO or RODI system?

The amount of pressure needed is dictated by the RO membrane. Factory specifications on our 50, 75, and 100 gpd systems call for at least 50 psi; and on our 150 gpd systems, 65 psi. You might get away with up to 10 psi less than these specifications, but be prepared for decreased performance in terms of how much water the membrane purifies, and how efficiently it performs. 

We recommend not exceeding 80 psi. There are components in many systems with maximum operating pressures of 100 psi. At 80 psi you can expect exceptional performance from the membrane.  If your line (plumbing) pressure exceeds 80 psi, install a pressure regulator (consult Buckeye Hydro) to reduce the pressure.  If you would like to increase your line pressure, install a booster pump.

 

Questions? Contact us at [email protected] or 513-312-2343


Welcome to Buckeye Hydro!
Pure Water Technologies

Our Newsletter

Sign up for exclusive updates and special offers!


Shipping

Buckeye typcially ships the same day, or less commonly, the day after an order is placed. The majority of our shipments are sent UPS Ground or FedEx Ground. Estimated delivery times for these services are similar, and are shown below. See our policies page for additional shipping information.

Read More About Shipping

FAQ

When should I replace my filters?
Will Buckeye filters fit properly in my water filtration system?
Do I need to do anything special when I install new cartridges in my RO or RO/DI system?

Read More FAQ