almost triple intex filter

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Charlie_R

Charlie_R

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TFP Expert
May 8, 2013
2,156
Mexico, MO
Got started on my triple "B" filter set, thought I'd post pics of it so far.

I have doubled the filtration capacity with this, and will be adding the third canister when I can find one. I've got an ad on the local craigslist, hoping that someone else might have one to get rid of.

According to this chart, Intex falls way short on their filter sizing.

FilterSize.jpg


Intex "B" carts are 15 sq ft, so by at least doubling the sq ft, I've brought the area quite a bit closer to what it should be.

What prompted my wish to do this was the amount of "blow through" I noticed with the single filter. Not wanting to go to a sand filter, mainly due to the high loss of water with the backflush/rinse cycle, I came up with this.







Note that I did leave provisions for the third canister when I find another one.

All connections between the Intex sized ports and normal 1-1/2" pipe are epoxied in with JB Weld.

As an added bonus, flow rate actually went up about 1/3 to 1/2 by guesstimate from the skimmer and return. Maybe mas985 can explain that one.
 
Just wanted to point out that we also recommend doubling the cartridge and DE filter sizes in that chart ... so the Intex is way undersized.

Flow rate increased because you lowered the head loss by increasing the filter size.
 
Thanks for that.

Already a noticeable difference in the filtering capability. a lot less silt and other fines left in the pool after vacuuming.

Now if I could teach the dogs to shower before getting in the pool......
 
JB Weld is being used as a filler/glue due to the difference in size between the Intex tubing and normal 1-1/2" PVC.

That hair dryer was being used for controlled heating of a length of PVC to bend it around the pool. Got that idea from an electrician friend. He custom bends conduit for some of his commercial work.
 
Charlie_R said:
JB Weld is being used as a filler/glue due to the difference in size between the Intex tubing and normal 1-1/2" PVC.

That hair dryer was being used for controlled heating of a length of PVC to bend it around the pool. Got that idea from an electrician friend. He custom bends conduit for some of his commercial work.
Click to expand...

Okay understand about the JB.

How did the pipe bending go, perhaps I missed a thread about it?
 
Lets just say things got a little damp, as in Missouri river in 1993 damp. But then I was running about 60 psi on a 3/4" line I had water cooled after bending. Do you know how much water can flow through that size pipe in one hour?
 
Charlie, great idea. I just lost a bearing in my Intex filter pump two weeks ago and thought I would "rebuild" my motor with new quality bearings and have the whole filter/pump thing as a spare, but that multiple filter thing really looks cool. I also have the fine silt/sand problem after vacuuming too.

Have you ever tried using the Unicell replacement cartridges for your intex setup. I got substantially more flow when I dumped the Intex stuff.

Am going to try and bend some 1 1/2 inch PVC next week for partial hard replumb.....mainly due to your bending thing would REALLY help out on some of my pool setup.

Thanks again for showing us how to improve our Intex setups!!

Bob E.
 

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In my sig line, I have noted that I use the Unicel C-5315 replacements for the Intex "B" carts. While I was still using the Intex, the silt problem was MUCH worse. I could see it coming back out in the return, clouding the pool.
 
Re: almost triple intex filter -- minor update

Just an update on the performance of the system as is, with only two canisters.

As noted in a previous post, flow rate has gone up. Which actually brings a new problem that I will have to take care of. When I attach my 1-1/4" vacuum hose to the intake, the pump goes into a slight bit of cavitation. The sound of the pump changes, to a bit labored.

I think purchasing a 1-1/2" hose will help, as will adding a ttw skimmer - valved, along with a dedicated 1-1/2" suction fitting just for the vacuum.

With the additional suction/flow rate, I finally broke down and bought a real vacuum head. Makes a huge difference in how long it takes to vacuum, and how much gets pulled from the water.

Still looking for another "B" sized canister (or more), don't need another pump motor. If anyone has one sitting around, let me know. I'll gladly pay postage. They are easy to separate from the pump section.
 
Decided to add this in here, since this thread is dealing with hard plumbing my pool, sort of.

I've gotten the returns almost completed, waiting on a bit of JBWeld to set.

A few pics:







What's really nice is to look out the kitchen window in the morning, and have to look for details to make sure there is still water in the pool. Here's a couple of water pics:





The red splotch in the first one is a reflection of the red umbrella my wife bought for our patio table.
 
Now that I've got the two returns working, I've noticed another difference.

I'm still using the stock toy skimmer that came with the pool. In the bottom of the outer canister, there is a black rubber "pump safety" valve ring covering slots around the bottom. With the stock filtering set-up, this ring stayed firmly against the bottom, effectively closing the slots. Now, I can feel good suction, and have observed that the ring is in fact allowing water through the slots.

I think it is safe to assume that with the lower head loss in the new plumbing, I have gained flow rate. Time to find a couple more filter canisters, or maybe next season spend a little for a regular AGP cart filter, if one exists for under $150. Or maybe even build one from a length of 12" PVC pipe.
 
Re: almost triple intex filter -- update

:oops: My use of JB Weld seems to have a glitch. Turns out that the constant water on the epoxy, along with the two materials being joined (PVC and ABS??) leads to a weakening of the joint.

After changing the filter cartridges, I forgot to open the return valves. :hammer: Turned the pump on, and the Intex fitting blew out of the 90. I lost about 2" of water before I could get the flood stopped.

Good thing I hadn't taken apart my original 2500 gph set! I've got it running the pool for now.

I tried to vacuum the pool today with the single filter, and had to stop midway to change out the cartridge, which didn't look that bad. So the assumption is that the increased filter area available with the (for now) twin filters makes a huge difference, especially when vacuuming. If/when I can find another canister -- I don't want to use the "back-up" unit for now obvious reasons -- I'll get it installed into the system. I'm betting this will improve things even more.

My thinking: If the pump is putting out it's rated 2500 gph (doubtful), this translates to about 41 gpm. With two carts in parallel, flow rate through each should be about 20 gpm. with a third cartridge in parallel, flow rate should go down to about 14 gpm through each filter. Plenty slow enough to catch the smallest particles the filter is rated for, while extending time between filter cleanings due to the much greater media area available.

Side note: You should see the dog hair these thing collect! Almost enough to become a prefilter on each cart.
 
Just an update and a question for the filter gurus. I've been thinking a little bit skewed with the filtration. Dangerous thing, right?

Anyway, I'v heard of some spa filters taking two carts stacked, with or without a short connection tube between them. So why can't I do that with an Intex canister? Maybe by cutting a canister in half, and extend the height to accommodate the double carts with a piece of large PVC pipe epoxied to the outside.

Anyone see any problems with this idea?
 
Re: almost triple intex filter -- update

Im a crafter, and a pool novice, but E6000 is the next best thing to velcro. Try that on a small connection. I have it on clothes, and even glued a handle back on a cup that went through many, many dishwasher washings. It never looses the flexibilty and hardens like JBWeld or Gorilla glue.
 
Gluing together PVC without the substantial overlap you get on a pipe fitting isn't the best idea. A filter is a pressure vessel, subject to quite a bit of stress. If the joint isn't perfect it can explode during use.
 

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