Seachem Purigen Organic Filtration Resin

Seachem Purigen is a synthetic polymer resin that goes in your filter like carbon does, but works differently. It pulls dissolved organic waste out of the water before that waste breaks down into ammonia, nitrite and nitrate. Seachem makes it for freshwater and saltwater tanks, and this page covers the 100 ml size.

Why remove organics early

Leftover food, fish waste and decaying plants release organic compounds into the water. Bacteria break those down into ammonia and then nitrite and nitrate. Taking organics out at the start means less of each down the line. Many keepers also notice clearer water, since organics are behind much of the yellow tint in older tanks.

The color tells you when to recharge

Fresh Purigen is light colored. As it fills with organics it darkens, through brown toward black. That color change is your cue that it’s used up. Unlike carbon, you don’t throw it away. Seachem designed it to be regenerated, so the same resin can be used many times.

How to use it

• Put it in a fine mesh media bag so the beads don’t escape. Seachem sells a bag made for it.
• Place it where water flows through it, not around it.
• Rinse it first to remove dust.

Recharging

Seachem’s instructions use a bleach soak followed by thorough rinsing and a dechlorinator soak. Follow the label exactly, wear gloves, and never put bleach-soaked resin back without neutralizing it. A conditioner like Seachem Prime handles the dechlorinating step.

What it doesn’t do

Purigen isn’t a substitute for water changes or a working biofilter. It also won’t remove nitrate already in the water at any useful rate. Keep up with routine maintenance and test regularly with a kit like the API Freshwater Master Test Kit.