The experiment.

A.O.

Well-known member
Apr 12, 2016
645
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Sorry this is a bit long.
So as some of you might know I normally fill my hot tub from my pool, due to the high iron content of my well water. Seems my sand filter cleans out the iron very well, If I have to fill the pool with the hose I'll get a green tint to the pool so I run a 24 hr filter session and it clears it all up. Whenever I (use to) fill the hot tub with the hose it would get a bit ugly, the cartridge filter would look like a coffee filter and I would get a bathtub ring in the hot tub. So I started filling the hot tub with my pool water and eliminated that problem. However, I have a Saltron mini in my hot tub which calls for 2000-2400 ppm salt, and my pool chlorine generator calls for about 3500 ppm salt which is too much for the hot tub. Normally I would wait for a big rain that would dilute the pool and I would fill the hot tub then. Lately we have had a big shortage of rain so that wasn't going to work and the other day my Saltron threw a code stating my salt level was too high and it quit working. Hmmm.. I've been debating getting a sand filter for the hot tub for a while and this forced my hand. I bought a small Intex filter for a small above ground pool., its like 950 gph pump/filter combo, finally got it yesterday and got it all set up and running. Drained half the tub and refilled with well water straight from the hose (I do have one of those hose end filters but not sure if it really does what it says) and got the new sand filter running , so tomorrow I'll pull the hot tub filter and see how it looks, I'm guessing it'll be pretty brown, I'll replace it and see how the replacement looks in a couple days and I'll report back.
 
Interesting 🤔
curious to see how it goes!
If you were closer I would have gladly donated my little old intex sand filter for your experiment.
Have you ever tried the polyfill trick? May be a bit easier than fooling with a separate filter set up. Not sure if you have a skimmer type area in your tub you could put polyfill in (perhaps encased in an old tshirt to be safe)
 
Thinkin' outside the box...

I can't say I know this is possible, but it should be (someone here would know): have you ever considered running your spa as part of your pool, instead of just filling it from your pool? The spa water would just circulate through the pool, so it would get filtered and SWG'd along with the pool water. When heat was called for, you'd isolate the spa and heat that, then when done spa'ing, you'd un-isolate it. Basically just run it like a typical pool with built-in spa.

Now if you want to keep your spa hot most of the time, that wouldn't work. But if you heat your spa each time you use it, it's something to consider. Then you could get rid of the spa filter and the spa SWG.

OR...

Replace the spa SWG with one that can share the same salinity as the pool SWG.

Either if your new filter idea doesn't pan out.
 
Interesting 🤔
curious to see how it goes!
If you were closer I would have gladly donated my little old intex sand filter for your experiment.
Have you ever tried the polyfill trick? May be a bit easier than fooling with a separate filter set up. Not sure if you have a skimmer type area in your tub you could put polyfill in (perhaps encased in an old tshirt to be safe)
I have not tried the polyfill but I do have a skimmer area in the tub, but then you have the polyfill mess to clean up when you are done. And I now already have the separate filter and if it works like my pool filter I'll be happy, and its just not that hard to set up.
 
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Thinkin' outside the box...

I can't say I know this is possible, but it should be (someone here would know): have you ever considered running your spa as part of your pool, instead of just filling it from your pool? The spa water would just circulate through the pool, so it would get filtered and SWG'd along with the pool water. When heat was called for, you'd isolate the spa and heat that, then when done spa'ing, you'd un-isolate it. Basically just run it like a typical pool with built-in spa.

Now if you want to keep your spa hot most of the time, that wouldn't work. But if you heat your spa each time you use it, it's something to consider. Then you could get rid of the spa filter and the spa SWG.

OR...

Replace the spa SWG with one that can share the same salinity as the pool SWG.

Either if your new filter idea doesn't pan out.
Whoa!! That sounds like a huge project! I have a stand alone hot tub sitting on a concrete slab that surrounds the pool about 10 feet away that would entail a whole lot of plumbing to hook them up. And we sit in that hot tub every day so it is always at temperature and ready for use. We elected not to have a built in connected hot tub for that very reason.
 
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I'm going to try a couple pics, tried earlier to no avail.
Ok, first is the filter set up, Next is the "coffee" filter next to a clean one, And the last is the "coffee" filter that has been dipped in Iron out.

IMG_1084.JPGIMG_1088.jpgIMG_1089.jpg

So I put the clean filter back in and will check it later for rust stains and if there I'll try the sand filter again.
 

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Ok, a little update on this. If you look on post 10 you will see the color of the filter after one day, looks like a coffee filter! These pictures are after two days filtering after running the sand filter for about 20 hours, much cleaner with only very minor streaks of the rust color in them! AND none of the brown bathtub rings in the tub the iron usually deposits. I am going to call this experiment a total success!! I am going to run that sand filter again tomorrow for the day to hopefully get the remainder of my iron. (raining today)
IMG_1091.5.jpgIMG_1092.5.jpg
 
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Whoa!! That sounds like a huge project! I have a stand alone hot tub sitting on a concrete slab that surrounds the pool about 10 feet away that would entail a whole lot of plumbing to hook them up. And we sit in that hot tub every day so it is always at temperature and ready for use. We elected not to have a built in connected hot tub for that very reason.
Oh man, @Newdude bet me 20 bucks I couldn't get you to tear up your plumbing and your yard. Thanks a lot pal! :mad:

But seriously, that hair-brained idea was inspired by others here that have tried to isolate their in-pool spa during the winter months, so that they could use it, and keep it warm. Honestly, I don't actually know if they got that to work.

I'm with you, and have often advised others, to ditch the in-pool spa idea (and expense!), which is nothing more than a concrete box with a handful of do-nothing jets and an uncomfortable concrete bench, and instead opt for a luxury fiberglass job with all the bells and whistles and seats and massagers, etc, etc. It's what I'd do if I was to ever build a pool with spa. The only downside of having the stand-alone spa is that you now have two water bodies so maintain. Seems like there would be a way to have the best of both setups: the standalone spa luxury with the ease of a single body of water.

Anywho, just thinking out loud. I can definitely see why you wouldn't want to go down that road. Good luck with the filters. It's probably just a matter of getting the right combo of gear.
 
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Oh man, @Newdude bet me 20 bucks I couldn't get you to tear up your plumbing and your yard. Thanks a lot pal! :mad:

But seriously, that hair-brained idea was inspired by others here that have tried to isolate their in-pool spa during the winter months, so that they could use it, and keep it warm. Honestly, I don't actually know if they got that to work.

I'm with you, and have often advised others, to ditch the in-pool spa idea (and expense!), which is nothing more than a concrete box with a handful of do-nothing jets and an uncomfortable concrete bench, and instead opt for a luxury fiberglass job with all the bells and whistles and seats and massagers, etc, etc. It's what I'd do if I was to ever build a pool with spa. The only downside of having the stand-alone spa is that you now have two water bodies so maintain. Seems like there would be a way to have the best of both setups: the standalone spa luxury with the ease of a single body of water.

Anywho, just thinking out loud. I can definitely see why you wouldn't want to go down that road. Good luck with the filters. It's probably just a matter of getting the right combo of gear.
I guess you better pay up then!
Years ago we looked into a site built hot tub and while they look good, they do not have all the goodies a stand-alone one does. And two bodies of water to take care of just doesn't bother me much, unlike what some people think, a pool or hot tub just is not that difficult to maintain!
 
I guess you better pay up then!
Years ago we looked into a site built hot tub and while they look good, they do not have all the goodies a stand-alone one does. And two bodies of water to take care of just doesn't bother me much, unlike what some people think, a pool or hot tub just is not that difficult to maintain!
The extra "goodies" of a stand alone would be worth the extra maintenance.

My fantasy pool build would be a stand-alone pool with a hollowed out area to the side, but on the other side of the pool's wall. A deluxe stand-alone fiberglass spa would fit into the hollow, maybe raised a little from the pool. Then I'd have a water feature on the pool wall in front of the spa, to simulate the typical spa spillover effect. Then coping around the spa to match the pool's. You'd have all the "look and feel" of the in-pool spa, with all the bells and whistles of a stand-alone spa. Something like that.

I'd have to work out how to get to the spa's innards, for maintenance or repair, or how to replace the spa if need be, but that could all be done with some forethought in the design.

They should invent/build/sell a drop-in fiberglass spa that could integrate with a pool in the same way an in-pool spa does. It would have all the goodness of a stand-alone, but it could share the pool water, with a spillover even, and then be isolated for the winter. Maybe such a thing exists, or it should if it doesn't. But this craze of spending, what $15-25K on an in-pool, that is just a slightly warmer, somewhat bubbly concrete box just never made sense to me. In addition to how much nicer the spa experience would be, this drop-in would likely be much cheaper to install, more reliable/repairable, and greatly simplify the pool build. Customers and builders would both benefit.

©2023 Dirkmerica Drop-In Spas, Inc. All rights reserved.
 
I guess you better pay up then!
Years ago we looked into a site built hot tub and while they look good, they do not have all the goodies a stand-alone one does. And two bodies of water to take care of just doesn't bother me much, unlike what some people think, a pool or hot tub just is not that difficult to maintain!
I agree! Going the tfp way makes both fairly simple. Then add some swcg’s & except for the enjoyment you almost forget you have them!
 
I agree! Going the tfp way makes both fairly simple. Then add some swcg’s & except for the enjoyment you almost forget you have them!
Yes, my pool came with a SWG (Reasonably expensive option) and a year maybe 2 after getting this Hot Tub I splurged and got the mini. So pleased with the results. SWG in the pool died after about 5 years and the replacement was $900 and change... money well spent. I still use those 3" pucks during the colder months.. but that adds my CYA for the next summer.
The extra "goodies" of a stand alone would be worth the extra maintenance.

My fantasy pool build would be a stand-alone pool with a hollowed out area to the side, but on the other side of the pool's wall. A deluxe stand-alone fiberglass spa would fit into the hollow, maybe raised a little from the pool. Then I'd have a water feature on the pool wall in front of the spa, to simulate the typical spa spillover effect. Then coping around the spa to match the pool's. You'd have all the "look and feel" of the in-pool spa, with all the bells and whistles of a stand-alone spa. Something like that.

I'd have to work out how to get to the spa's innards, for maintenance or repair, or how to replace the spa if need be, but that could all be done with some forethought in the design.

They should invent/build/sell a drop-in fiberglass spa that could integrate with a pool in the same way an in-pool spa does. It would have all the goodness of a stand-alone, but it could share the pool water, with a spillover even, and then be isolated for the winter. Maybe such a thing exists, or it should if it doesn't. But this craze of spending, what $15-25K on an in-pool, that is just a slightly warmer, somewhat bubbly concrete box just never made sense to me. In addition to how much nicer the spa experience would be, this drop-in would likely be much cheaper to install, more reliable/repairable, and greatly simplify the pool build. Customers and builders would both benefit.

©2023 Dirkmerica Drop-In Spas, Inc. All rights reserved.
So here is an abbreviated pic of my set up. Got the pool with the concrete surround and had them give me a peninsula off the corner for the hot tub, the cabana there has an outside bath and an equipment room for all the filters and such.
IMG_7973.JPG
 
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The extra "goodies" of a stand alone would be worth the extra maintenance.

My fantasy pool build would be a stand-alone pool with a hollowed out area to the side, but on the other side of the pool's wall. A deluxe stand-alone fiberglass spa would fit into the hollow, maybe raised a little from the pool. Then I'd have a water feature on the pool wall in front of the spa, to simulate the typical spa spillover effect. Then coping around the spa to match the pool's. You'd have all the "look and feel" of the in-pool spa, with all the bells and whistles of a stand-alone spa. Something like that.

I'd have to work out how to get to the spa's innards, for maintenance or repair, or how to replace the spa if need be, but that could all be done with some forethought in the design.

They should invent/build/sell a drop-in fiberglass spa that could integrate with a pool in the same way an in-pool spa does. It would have all the goodness of a stand-alone, but it could share the pool water, with a spillover even, and then be isolated for the winter. Maybe such a thing exists, or it should if it doesn't. But this craze of spending, what $15-25K on an in-pool, that is just a slightly warmer, somewhat bubbly concrete box just never made sense to me. In addition to how much nicer the spa experience would be, this drop-in would likely be much cheaper to install, more reliable/repairable, and greatly simplify the pool build. Customers and builders would both benefit.

©2023 Dirkmerica Drop-In Spas, Inc. All rights reserved.
On that show Insane Pools they had a homeowner who wanted a standalone spa & to their displeasure wouldn’t budge on the idea. They ended up making it fairly cohesive with the design but griped the whole time 🤣
 
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On that show Insane Pools they had a homeowner who wanted a standalone spa & to their displeasure wouldn’t budge on the idea. They ended up making it fairly cohesive with the design but griped the whole time 🤣
I'm sure they didn't make as much money as if they had built them one!
 
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I'm sure they didn't make as much money as if they had built them one!
They sure make some killer pools though- at that point money is no object lol 😂
The lady had already bought it, it was sitting there wrapped up when they showed up!
 
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Yes, my pool came with a SWG (Reasonably expensive option) and a year maybe 2 after getting this Hot Tub I splurged and got the mini. So pleased with the results. SWG in the pool dies after about 5 years and the replacement was $900 and change... money well spent. I still use those 3" pucks during the colder months.. but that adds my CYA for the next summer.

So here is an abbreviated pic of my set up. Got the pool with the concrete surround and had them give me a peninsula off the corner for the hot tub, the cabana there has an outside bath and an equipment room for all the filters and such.
View attachment 544143
Very nice setup up. Congrats!
 
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