To begin with, we have a somewhat rigged set up for our inground pool filter. The underground pipe from the sand filter that sends the filtered water back into the pool is broken. Rather than breaking up the concrete to replace it, we have it rigged with a large hose that leads from the filter back into the pool (placed over the side of the pool and tied to the ladder) to circulate the water. It has worked well for years this way; we just take the hose out of the pool when the filter is not in use so no one trips on it. The other day, with the filter completely off (and having been off for at least a solid day) we removed the hose from the pool as usual, and water kept coming through as though the filter was on. We didn't realize it for a bit, thinking that water was perhaps just draining from the filter... a few hours later, the water level had dropped drastically, almost below the skimmer. We were able to stop it by putting the winter plug into the skimmer - but clearly this is not a long-term fix. What could be causing water to pull through the skimmer like this when the pool filter is completely off?
- Jun 22, 2014
- 52,018
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome to TFP! 
Sounds like a siphoning effect. Once you removed the return hose from the pool and set it off to the side, it was at/or below the waterline level. That allowed water to flow (siphon) from the suction port (wall or drain) through the filter and then out the hose. Some multiport handle settings may allow that to happen. I bet if you place the handle on Closed or Winterize it wouldn't allow that to happen.
Pool Care Basics
Sounds like a siphoning effect. Once you removed the return hose from the pool and set it off to the side, it was at/or below the waterline level. That allowed water to flow (siphon) from the suction port (wall or drain) through the filter and then out the hose. Some multiport handle settings may allow that to happen. I bet if you place the handle on Closed or Winterize it wouldn't allow that to happen.Pool Care Basics
Thanks so much! I will give that a try and see if it makes a difference - I thought it was a siphoning effect as well possibly, but just found it odd that it has never happened before. Is there anything else you think it could be if that's not it?
If the air release valve is open or leaking, air could enter, allowing water to drain.
Thanks! Would an open/leaking air release valve allow water to drain not just from the filter but to continue pulling from the pool?
- May 3, 2014
- 62,676
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Actually the opposite. If you have an air leak in the system it would break the siphon.
So if it's something more complex than a siphon effect (which I won't know until I refill the lost water and unplug the skimmer) what are other things that could be causing this? I'm hoping that's all it was, but it seems odd that it has never happened before...
- Jun 22, 2014
- 52,018
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
If it was some sort of siphoning event this time, it could just be that in the past there was an air break in the process (lines) that stopped the flow of water. If you try to siphon from a long hose and get an air break somewhere, the flow stops, much like prime to a pump. But this time perhaps it was a perfect scenario where the hose was removed from the pool but the lines and filter remained full enough of water to allow more flow. Just a thought.
Hoping your thought is right... if not, I'll be back with more questions in a few days when I have time to check it all out again. Thanks all!!