Can anyone identify this equipment

[iowaguy27]

Can anyone tell me what this stuff is and what it's used for?

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[Huro]

It is a diatom filter it is used to polish/clean a tanks water, but they strip the water of all nutrients as I understand it.

 

[JessiNoel21]

Huro is correct it is as my dad would call it the first RODI unit it cleans everything out of the water. Even the good stuff you need in a tank.