Swimex questions

[cptkirk]

Considering having a Swimex pool installed in the home we are planning. It would be indoors. Have a couple of questions:

1. On the Swimex website FAQ, they don't recommend salt chlorination. To quote: "We recommend against the use of salt sanitizers. If not balanced properly it will lead to excessive chloramine being produced. This can cause fluctuation in pH and will make your water – and possibly air – corrosive, leading to rust on metal surfaces." While I know that the salt chlorine generator can cause pH rise, are chloramines any more of a problem than they would be with other forms of chlorine?
2. Since the pool will be indoors, some supplemental oxidation will be necessary as I understand it. Both UV and ozonators are offered as options. Which would be the better choice?
3. Swimex also recommends draining, cleaning, and waxing the surface (it is fiberglass) annually. Is this really necessary if the water is properly maintained?

 

[mgtfp]

I don't know much about fibreglass pools or indoor pools. But since nobody replied yet, I'll give my 2 cents worth, also to give the thread a bump, hoping that more will chime in.

My first thought was that it looks like Swimex is trying to make sure that they never ever have to pay for warranty claims.

Annual draining and waxing of the pool surfaces sounds like a complete waste of water and time to me.

A SWG is by far the easiest way to keep a pool "balanced". The continuous chlorination actually helps to break down chloramines quickly.

And yes, supplemental oxidation systems can be beneficial in indoor pools to accelerate CC breakdown. In outdoor pools on the other side, they are a complete waste of money, as you get free UV from the sun in surplus.

I really don't see pH fluctuations to be a problem with SWGs. Low pH is usually more of a problem when chlorinating with trichlor tabs, which are acidic and require regular baking soda additions to compensate the TA reduction caused by them, keeping TA high enough to offset the trichlor induced pH-drop by CO2 outgassing.

Salt water splash-out can be an issue for corrosion sensitive surfaces, probably more so in indoor pools that don't get regular rain induced cleanings. The answer is to simply not have corrosion sensitive materials around the pool.

By the way: Any chlorinated pool turns into a salt pool over time. Chlorine doesn't magically disappear after doing its job, it gets turned into chloride, aka salt. With an SWG, you simply recycle salt into chlorine, and you basically keep the salt level constant. With a manually chlorinated pool, you keep adding chlorine that eventually gets turned into salt.

 

[cptkirk]

There are a lot of variables here that are different from a typical outdoor pool application. The pool is small (probably in the 2600 gallon range), will be indoors, covered when not in use, relatively light bather load (typically one person for 1 to 2 hours daily). The pool will have stainless steel components that will be constantly exposed to the water (hand rails and parts of the paddlewheel system that provides the current that you swim against).

I like the convenience of SWG (which I'm very familiar with), but I am somewhat concerned about corrosion of the metal parts over time (should I be?). I'm thinking that maybe just dosing with liquid chlorine might be workable, using trichlor in a feeder if we are going to be away for a while (yeah I know that will eventually build up the CYA, but I'm thinking chlorine usage will be pretty small compared to a typical outdoor pool, and if the CYA gets too high draining/refilling wouldn't be that bad given the relatively small size). Thoughts?

Also, any thoughts on the relative efficacy of ozone vs UV?

 

[ajw22]

While SWIMEX does not recommend salt chlorination they appear not to have a problem with the salt accumulation that comes with using Trichlor tablets or liquid chlorine. If you don't regularly drain the pool you will end up with the same salt level as salt chlorination in a few years or more.

Every 3 ppm of liquid chlorine will add 5 ppm of salt to the 2600 gallons.

 

[cptkirk]

I don't *know* what the chlorine usage will be, but under the conditions described above I would tend to think it will be relatively light. Seems like it would take several years before salt accumulation reaches that of a SWG pool. If salt and/or CYA build up become issues over time, the relatively small pool volume makes draining/refilling feasible. The pool would be sitting on a sizable concrete footing, so not worried about it popping out. The pool does not require backfill on the sides.

If I did go with SWG, should I be concerned about corrosion of stainless steel parts that are constantly exposed to the salt concentrations typical in an SWG pool?

 

[Newdude]

If I did go with SWG, should I be concerned about corrosion of stainless steel parts that are constantly exposed to the salt concentrations typical in an SWG pool?

Pool quality materials are prone to deterioration from the elements alone, pool or no pool. With most liquid chlorine pools, they easily reach 5% -7% of seawater salinity while a 'salt pool' is about 10% salinity. The entire argument hinges on 5% or less difference between the two. (At the low end of the scale).

 

[Bperry]

I don't *know* what the chlorine usage will be, but under the conditions described above I would tend to think it will be relatively light. Seems like it would take several years before salt accumulation reaches that of a SWG pool. If salt and/or CYA build up become issues over time, the relatively small pool volume makes draining/refilling feasible. The pool would be sitting on a sizable concrete footing, so not worried about it popping out. The pool does not require backfill on the sides.

If I did go with SWG, should I be concerned about corrosion of stainless steel parts that are constantly exposed to the salt concentrations typical in an SWG pool?

Nearly every outdoor pool in existence has stainless steel ladders and railings and light niches that sit in the water (I know not all of them do). And I’d also imagine lots of of them use salt water chlorinators, mine does. I haven’t noticed any damage to those items in the 2.5 years of use. I think it’s a common misconception caused by the label “salt water”. It’s water with a little salt in it, not really salt water like the ocean salt water. Stainless holds up very well in boats and other usages around water (though not always submerged) so it holds up even better in the relatively low salt concentrations of a salt water chlorine pool.

 

[cptkirk]

I'm inclined to go with "conventional" chlorination as a starting position and see how that goes. If chlorine demand is higher than I expect it will be, I can always convert to an SWG later. Just need to make sure the plumbing leaves room for the addition of a salt cell without major rework.