Have Salt Systems fallen out of favor?

[PoolDoc]

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.