I have a 3 level stand and do electric brewing. The hot liquor tank is on top and for that I have one of those circular coolers from Home Depot. The boil kettle is on the bottom. My issue is I want to use the boil kettle to heat all the h2o and transfer it to the hlt on top. I have a vacuum pump from making wine and tried creating a vacuum in the hlt but to know avail. I think the issue is the hot is not airtight. I'm wondering if anyone has any idea on making the hlt airtight and if it is will it collapse under 20 mmg of vacuum.