This HOG1 or 1x on a customer's saltwater tank show a typical growth pattern after it runs for 6 months or a year. Every single grain of white Green Grabber® surface has growth attached, and you would not be able to brush the surfaces totally clean, because the growth would stay so attached that lots of growth would remain. If a scrubber reaches this stage, then it will survive almost anything except completely drying out. And, our UAS® upflow scrubbers (unlike waterfalls) can never dry out, because they are always underwater:

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