Welcome to the forum.
What were some of the reasons against SWCGs? Also, what were the alternatives for sanitizing they proposed?
Al
Just had a fresh water pool installed, but in the bidding/selecting process all PBs recommended against a saltwater pool....one even refused to install a salt pool. There were many reasons given for this....and all made sense...but none seemed like deal breakers. What's the REAL reason that PBs no longer favor salt pools? Are they losing too much money on warranty work?
Welcome to the forum.
What were some of the reasons against SWCGs? Also, what were the alternatives for sanitizing they proposed?
Al
Hi DB;
Is your pool in ground on above ground? Using an SWCG invalidates most AG pool warranties, due to increased corrosion.
Also, in dry areas, the salt can build up on the deck, and can be concentrated by evaporation enough to cause problems with both stone or concrete, and all metal components. In wetter areas, with frequent thundershowers, this is not so much of a problem.
PoolDoc / Ben
There are a few isolated areas of the country (such as parts of texas) where the local rocks do not do well with salt pools so builders that use natural rock are not installling salt pools but they are not falling out of favor in most locations. Consider that they have been around since the 60's I would have to say that they are here to stay.
Retired pool store and commercial pool maintenance guy.
All three of the PBs we received quotes from said that the salt eventually attacks/degrades the natural stone and/or leaves white deposits where it evaporates. One mentioned corrosion to pool equipment. But it was such an instant negative response when I asked about a salt pool installation...that I felt they weren't being upfront with me....that something else was making them recommend against a salt pool. We now have an IG, 15k gallon freshwater pool with flagstone coping and moss rock waterfall. This is our first pool experience....we were interested in getting a salt pool for all of the positives they offer and none of the negatives of a freshwater pool...but the pool builders convinced us to rethink our options. We also talked with six customer referrals and the verdict was 50-50 on salt pools.
Using flagstone coping, as standard, sounds like a local pattern. I'm pretty sure it's not an national one. But, *I'm* not sure I'd want to use salt on a pool with high evaporation surfaces, like waterfalls.
Regarding the positives you think salt has, I'd urge caution. They are commonly oversold as "eliminating pool chemicals", "chlorine free", "natural" and so forth. These are ALL bogus claims.
PoolDoc / Ben
Read somewhere in this forum that the cost savings of a saltwater pool are negligible after you figure in the cost of the system. You can buy a LOT of bleach, borax, and baking soda for the thousand or so that the SWCG will cost. You will still have to balance the pool chemistry the same way, just not use as much bleach as otherwise. If you want the "feel" of salt water, go ahead and add salt to your pool (I have done so and really like the way the water looks and "feels" though this is bound to be somewhat subjective! My salt level is about 2300 ppm as measured by test strips. SWCG's usually need a higher concentration of salt, but 2300 is plenty high enough for the feel benefits.)
10,000 gallon IG vinyl liner pool, BBB user, salt added to 2300 ppm (because it makes the water feel great!), new liner/new water on 6/23/11, algae-free since 2006 (at least that's as far back as I remember). 1HP Hayward 2-SPEED CONVERTED Superpump, Hayward sand filter, PS234 test kit.
Goal: To remain completely algae-free for the life of this new liner!
Life lesson: It is what it is.
12'x24' oval 9K gal IG pool; bleach; Hayward 244T sand filter; Hayward Super pump, 1 HP, 2-speed pump; 24hrs on low speedhrs; PS234; utility water; summer: ; winter: ; android phone; PF:13
I've said that SWCG's are roughly speaking, a financial wash. But I'd been thinking about that more specifically over the last few days. I installed (4) Pentair IC60 units on a 200,000 customer pool this spring, and have been trying to decide if I should add a fifth unit. Here are the numbers I've been considering:
IC60 Chlorine cost:
Cell costs
IC60 cell life: 10,000 hours, or 416 days => 'ON' time
IC60 'daily' or 24hr chlorine nominal production: 2 lbs chlorine gas equivalent.
IC60 likely actual production, over cell life: 70%
IC60 cell cost: ~$1,000
Cell life total production: 416 * 2 * 0.70 = 583 lbs of Cl2 equiv
Cost per pound (considering ONLY the IC60 cell!): 1000/583 = $1.72/lb
Electrical costs
Now, for my purposes, the electricity doesn't cost anything, because the customer does not (and does not want to) pay attention to it. BUT, here it is, anyhow:
Approximate 120V input: 2A or 120 * 2 = 240W
KWH/day = 240 x 24 / 1000 = ~8KWH
$ per KWH in Chattanooga = ~$0.10
$ for electricity over life of cell: 416 * 0.10 = $41.60
Cost per pound (for electricity) = 41.60/583 = $0.07/lb
Salt costs
But, there's another factor -- the salt. So far, I've put 3 pallets of salt into the pool, at a cost of about $1500. It's running low, and I'm going to have to have another pallet. This atypically high use, because this pool leaks about 1" per day. But, I'm going to spend $2,000 on salt for the season. With this pool, my salt will probably last 2 years between draining for various service issues, giving me an average cost of $1000 per year.
Total SWCG produced chlorine cost:
So, the cost per lb of Cl2 for salt -- higher than for most pools -- will be $1000 / $583 or $1.72 (again!)
So my TOTAL cost per pound of chlorine from the IC60's is $1.72 for the cell + $0.07 for the electricity + $1.72 for the salt, or $3.51/lb
Dichlor costs
Dichlor -- 50# at Sams for $106 + $9 tx = ~$115
$'s / lb dichlor = $2.30
lbs Cl2 per lb of dichlor (62%) = 0.62
$'s per lb Cl2 equiv = 2.3/0.62 = $3.71
On this particular pool, chlorine consumption runs about 70 lbs Cl2 equiv / week. So, I'm getting 56# x 90% (my estimate of current actual output) or 50# from the IC60's, and making up the balance with dichlor. But, because of my rapid water loss, I need to make up CYA, which the dichlor provides.
But, my overall cost per # of Cl2 is about $3.75 from either dichlor or the SWCG's.
Now, on a residential pool, costs for the CELL would typically be higher, because the cell cost per pound of SWCG is LOWER for an IC60 than for an IC20. But the water loss would be less (hopefully) and the salt cost would be less because of the volume profile -- this pool has a 4' deep shallow end, and a 13' deep deep end.
The result for my customer? They aren't saving anything.
However, the chlorine level is MUCH more stable, now that I don't have depend on a pool manager who is a great schmoozer (necessary at a country club pool) and on lifeguards who are flaky slackers, but un-fire-able because they are members.
So, costs are the same, but water quality is better.
By the way, just for comparison: *fresh* industrial 15% bleach contains about 1 1/4 lb of chlorine gas equivalent and costs $1 - $2 per gallon. That translates into a chlorine cost of $0.80 - $1.60 per lbs -- MUCH cheaper. However, handling bleach in large quantities is expensive and difficult. So, as usual there's no free ride.
My guess is that costs for CELLS will come down rapidly over the next 5 years, once Chinese units (like Intex's sucky one!) begin to be widely available AND improve in quality. I don't know, but I'd bet SWCG manufacturing is currently a high margin activity.
Last edited by PoolDoc; 07-16-2011 at 10:42 AM.
PoolDoc / Ben
The use of local natural rock is the reason they recommend against salt. Not all natural rock is created equal. Personally, I would worry about limestone used in any pool since it is a porous rock that is easily eroded and it is by no means chemically inert! IT will have impacts on your water chemistry and can be attacked by more than just salt. Realize that the use of local natural rock is not the only method of pool construction but is often used for cost considerations.
Retired pool store and commercial pool maintenance guy.
In addition to the cracking and deterioration of porous stone that is made worse by salt splash-out and evaporation leading to recrystallization pressure, there is also the increased metal corrosion rate from the higher conductivity of the water (around 3x or so) due to the higher salt levels and from stainless steel corrosion from chloride attack from its higher level. However, all of these types of problems can be mitigated through use of proper materials or procedures. Porous stone can be sealed or less porous stone used. More corrosion-resistant stainless steel can be used that contains more chromium or a sacrificial anode can be attached to the bonding wire and buried in moist soil.
In some cases, one does not have a choice because a material such as aluminum will be used in header bars and rails for automatic pool covers, for example. For "vanishing" electric safety covers where the aluminum header bar is immersed in the water, a zinc or magnesium sacrificial anode is recommended.
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