I’m afraid my intex SWG may not be strong enough. Help me find the best option.

[Brett S]

Intex makes two salt systems, they claim one is rated for pools up to 7000 gallons, which can generate 5g/hr of chlorine gas, and one they claim is good for pools up to 15000 gallons, which can generate 11g/hr of chlorine gas. About a year ago I bought the larger salt cell with a large 16” sand filter for my small 5000 gallon pool, knowing that I would be upgrading to a larger pool at some point. The system worked well for my tiny pool, but now that I have a larger pool I’m afraid it isn’t going to be enough. As my signature says, I now have a 14364 gallon intex pool, which is just barely within spec for the larger SWG (and, of course, manufacturers tend to be a bit optimistic on those specs).

The SWG really has very few settings, it always runs at 100% and can be configured to run in hour long intervals for anywhere between 1 and 12 hours per day. According to pool math, 11g of chlorine gas on my pool will raise the chlorine level by about .2ppm, so running it for the max of 12 hours will be able to add only 2.4ppm of chlorine to the pool per day. It’s starting to get warm here in Florida and right now the water temp is around 76-78 and I’ve been leaving the solar cover on for all but an hour or two while I swim. So far the SWG has been able to keep up and keep my FC steady at 5ppm but I’m already running it for 8 hours per day. I am afraid that as the weather and the water warm up even more, and since I won’t be keeping the solar cover on through most of the summer that there’s no way that it will be able to keep up with my chlorine demand in the middle of the summer.

So, I’m trying to figure out my options before I get stuck in a situation where I’m watching the FC drop with no way to raise it.

As I see it, I’ve got three options:

1 - I could completely replace the Intex pump, filter, and SWG with a better system. Obviously this would be the most expensive option, but if I got a two speed or variable speed pump it might wind up saving money on power consumption. I do have two concerns with this option. First, I only have 120V at the pool and it wouldn’t be very easy to get 220V there. It looks like there are some smaller pumps and SWG’s that will run on 120V, but it will probably limit my choices. Second, because this is an intex pool it is not bonded at all. Intex really doesn’t provide any options for bonding the pool and it’s my understanding that the intex equipment is specially insulated to keep it safe even though the pool isn’t bonded. I wouldn’t want to cause any potential issues by using other equipment that would require the pool to be bonded to be safe.

2 - I could keep the intex pump and filter, but replace the SWG with a better system. The intex pump and filter certainly aren’t the best in the world, but I think they are adequate for my pool. I still have the same concerns with the fact that I only have 120V at the pool and that the pool isn’t bonded.

3 - I could simply purchase a second intex SWG and run it in series with my current unit. This would cost less than $200, run on 120V and be designed not to be bonded. It would double the chlorine generation capacity to 22g/hr or a max of 4.8ppm per day, which I think would be sufficient to carry me through the summer.

So after all that, what do you guys think? I like the intex option because it’s inexpensive and will be easy to integrate, but I also know that intex doesn’t make the best equipment and if there are good reasons to spend more and go with something else (and the something else will operate on 120V and still be safe with an unbounded pool) then it may make sense to change everything out.

Thanks much,
Brett

 

[Brett S]

Oh, one thing I forgot to add is that my CYA is already at 80. I could potentially raise it to 90 or 100 to try to protect the chlorine from the sun a little better, but I know that over 80 really isn’t generally recommended and I’m not sure that raising it would really be enough to make a difference anyway.

 

[Newdude]

Oh, one thing I forgot to add is that my CYA is already at 80. I could potentially raise it to 90 or 100 to try to protect the chlorine from the sun a little better, but I know that over 80 really isn’t generally recommended and I’m not sure that raising it would really be enough to make a difference anyway.

That’s completely counter productive. You will need even more FC (that you’re already under producing) with the higher CYA. If you lower your CYA the sun will burn more FC per day. It’s a double edged sword.

 

[Brett S]

That’s completely counter productive. You will need even more FC (that you’re already under producing) with the higher CYA. If you lower your CYA the sun will burn more FC per day. It’s a double edged sword.

I would need a higher FC level with a higher CYA level, but the CYA protects the FC from the sun. So it’s my understanding that with a higher CYA level then the pool will use less FC day to day (especially here in Florida where the pool gets full sun all day every day) and as such my undersized system would have an easier time keeping up. Obviously I would need to maintain a higher FC level (and get it up to that higher level initially), but once the pool is at that higher level, then it should lose less FC each day because of the higher CYA level.

It‘s quite possible that I’m misunderstanding how this would work, though.

 

[Newdude]

Obviously I would need to maintain a higher FC level (and get it up to that higher level initially

So this is the million dollar question then. You can get yourself to target FC with liquid chlorine. But will the SWG be able to produce enough to maintain the higher FC even though the sun is depleting less ?

Hopefully one of the math gurus can figure out if 90 is feasible.

 

[Rattus Suffocatus]

3. I've seen them at the end of the season for $99, and I can't tell you how tempted I was to buy three of them last year like that from Wally for my inground. But I didn't want to kluge it up to do that to only save 50%... the Intex cells don't have a super long life from what I have read... I don't think that solution is as horribly ghetto as many others would think.. I'd probably suggest putting them in parallel if you could so your CSI isn't worse in one cell than the other.... I am sure someone will tell me why it won't work. You already know that it did on the half sized pool you used to have.

1 and 2 would be the preferred options from most. You'd have to decide your own cost options but you'd be upgrading everything that way...

The 4th option would be to supplement with liquid chlorine. You could try it to see if once at ideal FC it will hold it there. Math would be one way to do it. Trying it would be the other...

 

[markayash]

Interesting looking system,

So this is the million dollar question then. You can get yourself to target FC with liquid chlorine. But will the SWG be able to produce enough to maintain the higher FC even though the sun is depleting less ?

Hopefully one of the math gurus can figure out if 90 is feasible.

I like that option, let it run as much as possible and watch the level and if it gets low add a 1/4 gallon?

 

[Brett S]

One of the reasons I went with a SWG was to try to get closer to a set it and forget it type system and the convenience of not having to store or add liquid chlorine. So even though my SWG might be able to get 80% or 90% of the way there, having to keep liquid chlorine on hand and add it periodically kind of defeats the purpose. I definitely want to do something to provide more chlorination generation capacity.

In the interest of saving money, I went ahead and ordered another Intex SWG from Amazon the other day and it just arrived today. This is the new 2019 or 2020 model with ozone and unfortunately it is awful. It has 1.5” pipe fittings (with the funky intex threads), but internally the flow is heavily restricted. The incoming water is split with one part going past the ozone generator and the other part going past the flow sensor. But unbelievably the ozone generator only has a 3/8” opening for the water and the flow sensor only has a 5/8” opening. And that’s it... all the water coming in through the 1.5” pipe has to be squeezed through a 3/8” hole and a 5/8” hole.

So needless to say, this is going back to amazon and I just bit the bullet and ordered a Circupool SJ-40 from disountsaltpool.com. I paid nearly four times as much, but I figure that it’s much higher quality and it should last longer as well. It’s also starting to release my ties to intex, so if I do decide to replace the pump and filter at some point in the future then I’ll be in a better position to do so.

 

[mguzzy]

If I am reading your specs right you now have a pool that is just under 15K with a SWG that is rated for 15K. Its the recommendation here that you use a SWG with twice the rating of the size of the pool or a SWG rated or a a 30K pool in your case. That would give you some elbow room to vary the settings for the conditions otherwise you may be running your SWG at 100% for 24/7 to maintain your FC. And it then it could be a nearly set and forget setup. But with the two so close you will be forever having to add chlorine to get it close to target I fear. Play with the PoolMath App to see how that works.

 

[JeaniB]

I have the same pool with the same Intex sand filter/SWG. This is just my second season, but I bring my FC up with liquid chlorine at the beginning of the season and my SWG maintains well. The only time I have added liquid chlorine was twice after 6 kids in the pool all weekend. I keep my CYA 50. FC 4.0. My water is always clear!