Originally Posted by wayne and sherry
Yes, the tanks are not vented right.
X2 The vent hose loop is the fix. Most FW tanks have a "droopy vent hose" which allows water to siphon your FW out of the tank. If your tank is collapsing, you probably have a stopped up vent hose.
Replace the entire vent hose with a hose long enough to make a verticle loop and secure the loop at the top from falling to horizontal. I've seen this happen!!
Make sure the top of the loop is higher than the FW tank.
I don't personally recommend two loops as water can get trapped in the bottom of one loop and not allow venting. You can blow the water out, but no need to make a problem.
Make sure there is a screen in or over the exit to the vent line as critters will homestead in there given the chance. You can just wad up a piece of screen wire and stuff it in as long as air can get past it.
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