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Today on BRTV we have the top five ways to extend the life of your DI resin.
Hi I'm Nick host of BRSTV where each week we go over a new topic related to reefing.
This week we are going to give our top five tips on reducing DI resin consumption. DI
resin often has the highest ongoing cost of all the filters so it is wise to consider
ways to reduce this expense, starting with packing the resin correctly.
The mixed bed deionization resin is a mix of positively and negatively charged beads.
They need to be packed well or the two types of beads will separate in the cartridge and
the cartridge will be depleted prematurely.
Easiest way to know if you packaged it tight enough, is to look at the bottom of the cartridge.
If there is a big open space filled with water and no resin you know it wasn't packed tight
enough.
There are a lot of ways to pack resin but one of the most common methods is to fill
it a quarter of the way and tap it on a table twenty or so times to settle the beads, fill
another quarter of the way and repeat until it is full.
Once it is full use your finger to scoop out a small amount around the edge. This will
help keep the resin out of the threads when you replace screw the cap. Next insert the
foam ring and screw the cap on tight as it will go.
Number four cause of increased DI resin consumption is TDS creep which refers to the increased
TDS of the initial water flow when the system is turned on. When the RO membrane shuts down
there is high TDS water on one side of the membrane and very low TDS on the other. Once
the system is turned off the water on each side wants to find an equilibrium which causes
the TDS to rise in the product water side. Net effect is the first minute or so of water
coming out of the system has a higher TDS which can deplete your resin more quickly.
There are a variety of factors that will impact how big a deal this is for you. Many people
don't have to be too concerned because the initial burst of TDS is as low as 10 but others
it can be a hundred or higher and will have a fairly big impact.
Easiest way to deal with it is to simply not use the first bit of water that comes out
of the system. However most of us have the tubes hooked up to storage tanks so disconnecting
it can be a pain. We find it is easier just to add a three way valve which allows you
to redirect the initial surge down the drain and switch it back just as easily.
The third way to extend your DI cartridges life is to maintain your membrane properly.
A good performing membrane operating in ideal conditions will remove as high as 98% of the
TDS so the DI has very little to remove. Generally speaking if you have one TDS going into your
resin and your friend has twelve TDS feeding the membrane yours can literally last twelve
times as long.
This means you may only need to change yours once every six to twelve months and they might
have to do it as often as every two to four weeks. Now there are more factors than that
such as variances in C02 but for the most part this statement is generally true so you
can see why it is important to maintain your membrane performance.
Best way to do that is to use a high quality membrane with a high rejection rate like the
DOW Filmtek 75 GPD and flush the deposits off frequently using a flush kit. The biggest
factor with membrane performance is feed pressure so make sure you are feeding the membrane
at at least 50 PSI. If not, the cost of a booster pump might be cheaper than your yearly
DI resin bill.
One of the biggest causes of pressure drop and reduced membrane performance is a clogged
sediment filter so make sure to keep an eye on that filter. They are super cheap and it
is way more cost effective to maintain the sediment filter than it is to keep burning
through DI resin.
The number two cause of increased DI resin consumption is improper storage. This is both
at your home as well as where it was purchased. Resin is depleted when it comes in contact
with carbon dioxide in the air surrounding it. If you the cartridge you bought is packaged
in simple shrink wrap and you had to dust it off when buying it you are likely buying
it from the wrong place.
Ideally it should be contained in a thick mylar bag capable of preventing gas exchange,
even better a foil lined mylar bag, better than that, vacuum packaged as well. Only other
thing I'd look for is make sure to buy it from a vendor you know is moving through large
volumes of media so you know it is fresh.
Think of it like going out for sushi, I'm not eating there unless the place is busy
and it is clear they have fresh product. Again, if the resin is sitting on a shelf covered
in dust look elsewhere.
The number one and biggest cause of increased DI resin consumption is high levels of carbon
dioxide in your water supply. The easiest way to know if your levels are too high is
to use some of the calculators available online.
Best solution for this is to fill your storage container with RO water first. Then throw
in a pump or air stone to let the excess C02 gas off over a couple days and then use a
dosing pump, slow gravity feed or other solution to send the water through the resin. You should
try to limit the flow through the resin to a few gallons an hour similar to your RO systems
flow rate for best results.
To be honest this is kind of a pain, when most people do the math on the cost of setting
this up, space and time consumed they would prefer to just buy more resin. Possibly in
larger most cost effective sizes. So check out the comments are down below and
tell us how long a resin cartridge last you and what you have done to increase performance.
if this is your first time with us, we do this every week so hit that subscribe button
and give us a thumbs up. See you all next week with another episode of BRSTV.