I found that the airflow was not reduced by just spacing them. If you can not find the plastic spacers you can use some 1/4" semi-rigid tubing from a RO/DI unit.
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When you think you know everything they give you a Bachelor's,
When you realize that you know nothing they give you a Master's,
When you realize you know nothing but it is ok because they don't ether then you get a Doctoral. | 
