Air Water Ice 10 inch Color Changing DI Resin Cartridge

A standard 10 inch deionization cartridge packed with colour changing mixed bed resin, and the final stage that takes RO water the rest of the way to zero TDS. The resin starts blue and turns amber as it exhausts, so you can see how much life is left instead of guessing. Browse our other RODI systems and parts.

How Colour Changing DI Works

Reverse osmosis gets you most of the way, but the last traces of dissolved solids need ion exchange. This cartridge holds 1.25 lb of ResinTech MBD-30, a 1:1 volumetric mixture of CG8-H, an amber hydrogen form cation resin, and SBG1P-OH-ID, a dyed hydroxide form type 1 porous strong base anion resin. The anion component is infused with a permanent indicator dye, so as the bed exhausts it moves from blue toward amber, top to bottom, in the direction the water flows.

ResinTech rates MBD-30 to deliver demineralized water with a resistivity in excess of 18.3 megohm. For a reef tank that means RO/DI water with nothing left in it to feed nuisance algae or push your parameters around.

Features

Specifications

Capacity in real use depends on your source water. The ppm TDS rating is a total load figure, so the higher the TDS reaching the DI stage, the sooner the colour front moves.

Get the Most From It

DI resin is the most expensive stage in an RO/DI unit per gallon, so it pays to protect it. Keep the sediment and carbon stages on schedule, replace the RO membrane when its rejection rate drops, and the DI will last considerably longer. If your DI is exhausting quickly, the membrane is usually the reason rather than the resin.

Pairs With

• Dow Filmtec RO membranes, the stage that determines how hard your DI has to work
• HM Digital TRM-1 triple inline TDS meter or the handheld TDS-3 to confirm zero
• 10 inch clear refillable cartridge if you would rather refill from bulk resin
• RODI systems and replacement filters

FAQ

How long will one cartridge last?
It depends entirely on what reaches it. The resin is rated at 6,800 ppm TDS of total load, with a minimum 3,000 ppm across most water profiles, so a low TDS feed from a healthy membrane stretches it a long way and a failing membrane burns through it.

What do the colours mean?
Blue is fresh capacity. Amber is exhausted. The change travels in the direction of flow, so watch the outlet end and swap the cartridge when the colour reaches it.

Does it work in a non-clear housing?
It filters exactly the same, you just lose the benefit of seeing it. If your housing is opaque, run an inline TDS meter and change on the reading instead.

Can I refill it instead of replacing it?
Yes, the 10 inch body is refillable. Bulk colour changing resin is sold separately.

Is this the same as separate anion and cation cartridges?
No. This is a mixed bed, both resins blended in one cartridge, which is the usual single stage DI setup. Separate anion and cation cartridges are a different, more specialised arrangement.

Do I need DI at all if I have RO?
For a reef tank, generally yes. RO alone typically leaves some TDS behind, and DI is what takes the last of it out to zero.