I would go with a inch in your main tank and 2 to 4" in your refuge. I think it would be more benifit you have rubble rock and such in your refuge rather than algae as there is no fool proof way of preventing algae from spreading to your main tank. but if you are ok with this then fill your boots
. Personaly I will never again prouposly introduce algae to any system I own
Steve
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*everything said above is just my opinion, and may or may not reflect the views of this BBS, its Operators, and its Members. If cornered on any “opinion” I post I will totally deny having ever said this in a Court of Law…Unless I am the right one*
Some strive to be perfect.... I just strive.