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Gutbucket
04-05-2006, 11:54 AM
I'm quite tempted to go salt, just hung up on the cost to do so. In addition to the inital outlay for the unit ($1200 or so) and the salt (not much I think). What are the actual operating costs: electricity and replacement cells? Also how often do the cells need replacing if I use Sodium Hypo to shock and just use the SWG to provide baseline chlorination?

waterbear
04-05-2006, 12:11 PM
You also have to look at the convience factor that you get from using a SWG. It is hard to put a dollar amount on that but IMHO it far outweighs any additional costs that may be incurred. As for the life of a cell--there are many factors invovled such as salt concentration, water hardness, operating temperature, pump run time, cell output setting, etc. Most cells are rated in hours of operation. Given all the variables your milage will vary. My system (Aqualogic PS-8 by Goldline) is new so I have never had cell problems. Haven't even needed to clean it yet and it's been in constant operation since lst Nov. My brother has a salt system that is over 6 years old and he is still on the original cell and going strong---don't know what kind it is though.

gwrace1
04-05-2006, 12:31 PM
I would suggest you check out Aquarite prices on Ebay. I picked up a brand new unit from a pool dealer last year for $400.00. It seems to be working great on my AG 26000 gallon pool that was installed this spring. It came with a 5 year prorated warranty.

It did require about 600 lbs of salt, but that was the only other expense. I have a two speed pump and am running the unit on low speed for 12 hours a day. Seems to be holding chlorine at the right levels. I just didn't want to be bothered with constant bleach purchases and additives. This is far more convenient.

mwsmith2
04-05-2006, 12:59 PM
I share similar experiences with those above. I got mine on fleabay too, for right around the same price. Salt is cheap, its the same thing used in water softeners. They only way your salt goes down is from pumpout, splashout or dragout. I've been running mine just about over a year, and have yet to have the "check cell" light come on. I'm going to pull it out just to take a peek at how it looks, but it's pretty low maintenance.

Yes, definitely use bleach to shock, instead of the cell. However, since i've had the SWC, my CC has dropped to 0 and stayed there. I haven't shocked the pool in over a year.

Michael

KurtV
04-05-2006, 02:09 PM
You also have to look at the convience factor that you get from using a SWG. It is hard to put a dollar amount on that but IMHO it far outweighs any additional costs that may be incurred.

Good post and good answers so far, but I think Gutbucket is asking a slightly different question than the one that's been answered. While (most) everyone acknowledges that SWGs are a great convenience, that convenience comes at a higher price, especially when compared to the "grocery store" school of pool water care. While for Waterbear and others, at the price he/she is paying (initial + operating + maintenance), the benefit "far outweighs any additional costs that may be incurred", that isn't the case for everyone (or anyone at some price point). That cost/benefit ratio breakpoint is pretty high for lazy spendthrifts like me but much lower for the more industrious, frugal types. What I (and I think Gutbucket) want to know is, what are your true total costs? What is the average daily electricty appetite of the SWC (if it's non-trivial)? How often do you have to add salt? We know that cell life is expressed in hours of operation, how does that translate into years of "normal" operation?

I know there were some very informative posts on this on the old forum. Did any of you who've done those calculations save that information?

Michael: Thanks for Bleachcalc (though you should probably rename it since it now does so much more); it's very helpful.

waste
04-05-2006, 03:01 PM
There were quite a few good responses posted on this when the 'old' forum was available, unfortunately, those are gone right now (and perhaps... (shudder)... forever).
As I recall (do you trust my memory of the old posts?) they were usually not excessive. However, I do recall a number of(something between 'a few' and 'quite a few') responses for short life on some SWGs. As I recall, the most short lived were the ones that didn't have the 'auto-reverse polarity' function.
If you, and your wife or children are the 'we can do this ourselves' sort - bleach is the way to go. If you want less involvement in your pool, get the SWG.

I don't know your financial situation. If you can afford it, I'd go with the SWG. Hell, even if you can't, adding salt (it's cheep) might increase the 'feel' of the water.
This response is incomplete, but other members will add on, as neccesary (and I'll keep my eye on it).

You came to the right place - stick with the pool forum!

mwsmith2
04-05-2006, 03:05 PM
I add salt very rarely. Maybe 40# in the past year. I wouldn't worry about the cost of salt. Figure 1 gallon of acid per month during the summer. I can't see how the electric cost would be more than $10/month. Truthfully, you are going to be able to do it cheaper with bleach. But, when I was doing bleach, I had to add .75 gallons every 3 days, without fail. Even then, I was skirting 0.5 Cl. I always had about 0.5 PPM CC, and a slight Cl smell. I don't have any of those problems now with a SWC

Gutbucket
04-05-2006, 04:15 PM
[QUOTE=KurtV]What I (and I think Gutbucket) want to know is, what are your true total costs? What is the average daily electricty appetite of the SWC (if it's non-trivial)? How often do you have to add salt? We know that cell life is expressed in hours of operation, how does that translate into years of "normal" operation? QUOTE]

Yes! my questions exactly. I'm certainly convinced about the convenience factor. I'll poke around the online auction sites and see what I can find. The issue for me at the current point in time is that there are too many more important house & pool projects that require the time/energy/funds I'd spend getting and setting up a SWG to justify the convenience and nice water feel I'd get in return. Thank you all for your responses.

waterbear
04-05-2006, 04:32 PM
Yes, definitely use bleach to shock, instead of the cell. However, since i've had the SWC, my CC has dropped to 0 and stayed there. I haven't shocked the pool in over a year.

Michael

Seems there is more than a convience factor going on here. I also have never had nay CC since my unit went operational last Thanskgiving and have never shocked my pool with the unit or added bleach... The abiltiy to maintain less then .5ppm CC is also a health factor, IMHO!;)
But then again I'm just a guy with a big mouth, bigger opinions, and enough knowledge to be dangerous! (glad that's finally out. I feel much better now!);)

Brock
04-05-2006, 06:34 PM
Warning newbie SWG questions here. What do the actual cells run on? 120vac I assume, what are they rated for UL wise 2 amps, 5 amps? How do they know if water is being passed through the cell? Is the cell powered from the same circuit as the pump? I mean if the pump is on a timer does the cell need to be on the same timer or do they somehow know when it's on or not? To me the selling point might be the fact the pool can sit at .5 free all by itself.

waterbear
04-05-2006, 06:39 PM
Warning newbie SWG questions here. What do the actual cells run on? 120vac I assume, what are they rated for UL wise 2 amps, 5 amps? How do they know if water is being passed through the cell? Is the cell powered from the same circuit as the pump? I mean if the pump is on a timer does the cell need to be on the same timer or do they somehow know when it's on or not? To me the selling point might be the fact the pool can sit at .5 free all by itself.
Mine is hardwared into the house wiring and it is plumed with a flow switch so it will not run if the pump is not on. Moot point on mine since I have the Aqualogic which also controls my pumps, lights, heater, water features, etc.
The electrician who my builder subcontracted pulled a new circuit for all my pool stuff.

Mark_WATERMAID
04-05-2006, 07:35 PM
Hi Brock

The cells run on relatively low voltage DC. You will find that the life of the cell is directly related to the applied voltage. The higher the voltage, the lower the cell life. In fact if you push the voltage over 11.4 volts, the electrodes become jump electrodes and although the cell will produce more chlorine, you are sacrificing cell life to get it. The amperage that you ask about is not nearly as critical as the voltage. In fact you can push the amperage quite high as long as you don’t exceed critical voltages.

As far as pumps and chlorinators go, all chlorinators are wired with the pump so that when the pump is on the chlorinator is powered. Pump off, chlorinator off. Some units use mechanical flow switches with springs and some use electronic switches with no moving parts to shut down the system when flow stops

Mark Manning
President
Watermaid Canada
www.watermaid.ca
mark@watermaid.ca

Mark_WATERMAID
04-05-2006, 09:18 PM
I can speak for Watermaid but don’t have numbers for the rest of the units out there. I don’t suppose that it will be much different for the rest of them. The total cost to run a Watermaid unit for a season is between $70.00 and $80.00 maximum. This includes chemicals and electricity and assumes that the unit is run at 100 % 24 hours a day for the entire time. One note for everyone, I am in Canada so our pools are seasonal here. This is the cost to run a full 5 months. To compare, the average cost to run a pool on regular chemicals in Canada is $400.00 per year.

Mark Manning
President
Watermaid Canada
www.watermaid.ca
mark@watermaid.c

PatL34
04-08-2006, 10:49 PM
I did do a check of the running costs a few years back, but did not keep a record of the calculation, so here goes for another try.

Monthly Electric Cost
--------------------
240 volt 2 phase supply at 1.0 amp = 240 watts. This is the value of the supply to the transformer in the DG220 Control Unit only.

So 240 X 12 hours/day = 2880 watthours X 365/12/1000 = 87600 watthours = 8.76Kwh per month X $0.1/Kwh (per OUC rates rounded) = $8.76/month

Monthly Cell Wear Cost
----------------------
Assume $550 replacement cost, 5 year life, 12 hours/day for 365 days.

550/5 years/12 months/2(1/2 day) = $4.6

Monthly Muriatic Acid Cost
-------------------------
2 gallons @ $3.67 = $7.34

Total Monthly Cost = 8.76 + 4.6 + 7.34 = $20.7

(Corrected values applied in this post)

Any upsets and extra chemicals like baking soda, Borax, and incidental bleach are not included.

Hope this helps, and if there any questions, please let me know.

Pat

KurtV
04-08-2006, 11:14 PM
Pat,
Thanks for the info. One minor quibble; the average residential electricty cost in the U.S. in 2003 was 8+ cents per kilowatt hour.

http://www.eia.doe.gov/cneaf/electricity/epm/table5_3.html

Brock
04-08-2006, 11:48 PM
Yup, actually I would bet it is closer to $.10 now. On the other hand did you actually take a reading off the power supply for the unit or was that just what it was rated for? 24w does seem reasonable for what it is doing though.

At 8.76 kw per month at $.10 is still $.876 a month so you have the cost correct, maybe slipped a decimal?

PatL34
04-09-2006, 09:11 AM
I went and did a further measurement to check my original figures, and did in fact read my amp meter incorrectly.

The electric cost should be 1 X 240 = 240 watts x 12 hours daily running time = 2880 watthours X 365/12/1000 = 8.760Kwh X $0.1/Kwh = $8.76

Total cost = 8.76 + 4.6 + 7.5 = $20.86

This seems to compare with what I calculated previously 2 years ago.

Sorry about the error.

Pat