changing Fox sand filter for first time on my own........

JBird

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Sep 17, 2010
22
trying to save some money. I have looked up directions and the pool store guy who sold me the sand showed me the basics as well. My question, I think, has an obvious answer but had to ask. My Fox filter appears to be sitting on a stand, that may be built on or not, and I can't find a drain plug on the outside of the stand. So I assume the drain plug is underneath. So that appears to mean that I am going to have to loosen the filter from the pvc water lines so I can tilt the filter enough to get to the drain plug. Is it necessary to drain the water out from the plug or can I just use my shop vac to get the water and sand out? I hate to increase the trouble by having to pry the fittings loose on the pvc.

Thanks,

J
 

PoolGuyNJ

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May 20, 2007
3,192
South Central NJ
Sucking out the sand without draining the tank is ponderous. I assume you have a shop vac. Remove the pump lid. Put the multiport in rinse and suck the water out the backwash port. That will remove about 90% of the water. Keep it going for a while and the results will be even better. Less water in the tank = easier vacuuming of the sand.

Scott
 

duraleigh

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Scotts advice is certainly sound but I am not a big proponent of changing sand to begin with. Are you changing it for a reason?
 

PoolGuyNJ

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May 20, 2007
3,192
South Central NJ
If this is a red, fiberglass wrapped tank, parts like gaskets can sometimes be hard to come by.

I usually suggest a home owner remove 50 to 100 pounds from the top. The rest of the sand is fine. Unless your getting sand in the pool or converting from Baquacil, there is little need to go that deep. After 10 years, the sand starts getting somewhat polished. If the pump was over sized, I would also expect this to happen somewhat faster.

Scott
 

JBird

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Sep 17, 2010
22
PoolGuyNJ said:
If this is a red, fiberglass wrapped tank, parts like gaskets can sometimes be hard to come by.

I usually suggest a home owner remove 50 to 100 pounds from the top. The rest of the sand is fine. Unless your getting sand in the pool or converting from Baquacil, there is little need to go that deep. After 10 years, the sand starts getting somewhat polished. If the pump was over sized, I would also expect this to happen somewhat faster.

Scott

It is the red, fiberglass wrapped one. I do not appear to be getting sand in the pool. The sand hasn't been changed in at least 5-6 years. All of the sudden I can't get enough pressure. Basically 8 when I am used to running at around 18. My pool company suggested that this may be the problem. I can't find anywhere that the lines have an air leak in them. My pump motor is only a month old. It was working great. Sounds normal now. I didn't want to spend the money right now to have the pool company change it. Business is bad enough that I need to do what I can on my own. Do you know if this filter has the drain plug under the bottom? Under the stand? Do recommend I shop vac the water out to get to the sand?
 

JBird

Member
Sep 17, 2010
22
PoolGuyNJ said:
Sucking out the sand without draining the tank is ponderous. I assume you have a shop vac. Remove the pump lid. Put the multiport in rinse and suck the water out the backwash port. That will remove about 90% of the water. Keep it going for a while and the results will be even better. Less water in the tank = easier vacuuming of the sand.

Scott
Thanks, I will see if I can figure that out. So with the multiport in rinse do I suck the water out of the backwash port by running the pump, or using my shop vac?

Jay
 

duraleigh

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Basically 8 when I am used to running at around 18. My pool company suggested that this may be the problem.
Well, I would stay a long way away from that pool company. The only way the sand could be the culprit in a loss of pressure was if you spewed about 60-70% of your sand into the pool floor.....essentially emptying the filter.

A FAR more likely scenario is you have a suction side blockage. Somewhere between the skimmer(s) and the impeller, you have a restriction which is slowing the flow. My first check would be to remove the pump basket and very carefully reach inside the pump and check the impeller for clogs. If the impeller is clean, then you can start working your way toward the skimmers. I'll be surprised if you don't find a restriction or blockage somewhere along that path.

It's your call but I think you'll find changing the sand to be a waste of your time.

Do you have any reason to suspect the gauge may not be working properly? Can you tell the flow is reduced at the returns in front of the pool?
 

JBird

Member
Sep 17, 2010
22
duraleigh said:
Basically 8 when I am used to running at around 18. My pool company suggested that this may be the problem.
Well, I would stay a long way away from that pool company. The only way the sand could be the culprit in a loss of pressure was if you spewed about 60-70% of your sand into the pool floor.....essentially emptying the filter.

A FAR more likely scenario is you have a suction side blockage. Somewhere between the skimmer(s) and the impeller, you have a restriction which is slowing the flow. My first check would be to remove the pump basket and very carefully reach inside the pump and check the impeller for clogs. If the impeller is clean, then you can start working your way toward the skimmers. I'll be surprised if you don't find a restriction or blockage somewhere along that path.

It's your call but I think you'll find changing the sand to be a waste of your time.

Do you have any reason to suspect the gauge may not be working properly? Can you tell the flow is reduced at the returns in front of the pool?
I don't have reason to think the gauge is incorrect. I can see the skimmer isn't drawing water like it should. I thought there might be a restriction as well. I tried using a snake to run through the line but could not get it to turn at the L in the pipe. I tried it from both ends to no avail. Two different snakes as well. I will check the impeller. The motor sounds normal if that means anything. Brand new as already mentioned.
 

JBird

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Sep 17, 2010
22
I should add that I used my shop vac and tried to vacuum the line from the skimmer to loosen anything that was in the line between the skimmer and the pump, with no success. I don't know how to otherwise "blow" the lines.
 

duraleigh

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Check the impeller. If not there, search "drain king" on this forum or the web to blow your lines backwards.

When the pump is running, is the pump strainer basket full to the very top with water? Any bubbles?
 

JBird

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Sep 17, 2010
22
Yes the basket is filled up. I had to add water to it to fill it up. I think there is some bubbles when I start it up. I can recheck that. What will that mean? Other than water is coming through the line. I noticed when I put it on backwash that I am getting decent flow in the skimmer. when I put it on filtration, I get less, and weak flow.
 

duraleigh

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I noticed when I put it on backwash that I am getting decent flow in the skimmer. when I put it on filtration,
What is the psi when you run it in "backwash" mode? What is the psi when you run it in "filter" mode?

A few bubbles on start-up is no big deal.....you do not want to have bubbles continuously visible in the pump strainer basket.
 

JBird

Member
Sep 17, 2010
22
I bought a drain king and used it facing away from the pump and was able to get flow into the skimmer. Then I started running the pump and I could see that the psi was going to go higher than it had been running, which was around 8. As it passed 10 and was moving well, all of the sudden I lost pressure and got a splash from the cover on the pump bucket. The lid was on tight enough but the pressure caused the splash. Then the pump would only produce around 4-5 psi. I thought I had it for a moment. Before that the psi was 8 through the filter and about the same to slightly less for a backwash. Now neither is really moving the needle much. The engine sounds slightly less aggressive. It is only a month old. It doesn't sound bad but not as strong. I haven't taken it off the pump to see if anything is in there. I ran my fingers from the bucket into what I believe is the impeller and don't feel anything that would seem abnormal. So it is worse now. The drain king seems like a handy thing to have around though.
 

duraleigh

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As it passed 10 and was moving well, all of the sudden I lost pressure and got a splash from the cover on the pump bucket.
I don't understand what you mean. Did water splash out of the pump basket? Was there air/bubbles/turbulence inside the pump basket?
 
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