Clearing Up SWG Confusion

[Seadweller]

Yes, I'm the one that's confused, and unfortunately, it's my nature to research things to death before pulling the trigger on a major purchase....

1. Over-sizing - I'm clear on this, for the most part, but....There's seems to be an "acceptable" range for over-sizing, which for my 25K gallon pool, would mean anywhere from a 40K to 60K system. I understand the concept of running the system at a fraction of it's output for longer service life, but there must be a point of diminishing returns.

2. System Output - To make things more complicated, one system designed for a 60K gallon pool generates the same chlorine as another system designed for a 45K gallon pool. I spoke to the company that makes the 60K gallon system, and they said it would be more than perfect for my pool. It is rated for 2lbs per day, so does that mean any system rated at 2lbs per day would be sufficient, regardless of it's "up to XXX gallons" rating? Or, is there no common criteria for these measurements?

3. Weighing Cost/Performance - The higher the output, the more expensive the system and replacement cell. For example, I could buy the 45K gallon unit on sale, and two additional replacement cells, for the same upfront cost as the 60K unit. At what point does over-sizing become cost prohibitive?

4. Adjustment Ranges - Some units allow finer adjustments, while others allow for adjustments in increments of 25%. I understand the benefit of finer adjustments, but how common is it that you'd be in between the ranges offered by a simpler system? From what I've read, the % adjustment merely controls the on/off cycle of the cell, which runs at 100% when it's on. What's the difference between operating the unit for 4 hours at 100%, or 12 hours at 25%? The cell is still operating at 100% for the same period of time, right?

5. The Ultimate Decision - For a 25K gallon pool, does it make sense to over-size further to a unit that produces 3lbs/day, or is that overkill? It seems 2lbs/day should be more than sufficient for a 25K gallon pool, so what am I missing?

Thanks! I'm going to order one tomorrow....

 

[dschlic1]

A lot of the sizing information is hype. If you can get the actual chlorine production per day, I would use that for calculating best price per output. Some units not only use time based cycling, but also use voltage steps. I run my SWCG at between 20 to 30% for eight hours a day, with more than acceptable life. My first cell lasted seven years. I fully expect the second to last as long.

For sizing, you will need to calculate how much chlorine you need on a daily basis. For my pool, I need two to three ppm chlorine per day. If you have an existing pool, you can probably calculate you chlorine needs from the amount of chlorine you add over a period of time. Usinig that information, you can get a rough estimate of what duty cycle for what system you are looking at.

 

[BasicTek]

As someone that is 4x oversized I'd highly recommend being as oversized as you can to a point
I never dial in 25% 50% etc it's always somewhere in between
My SWG is rated at about 1.45lbs per day and it has been generating almost double that per the calculator based on my average daily chlorine draw so I'm not very confident in the published ratings
It would be really nice if someone could actually test the top brands and verify the actual amount of chlorine they generated instead of us only having the ratings to rely on. I.E car manufacturers may give an estimated 0-60 but you can get actual from enthusiast from car and driver, etc.

Another thing that might allow you to size smaller is compensating with inline chlorinator or floater. I had a ton of 3" pucks leftover when I converted and I use them to add CYA. As a benefit they also allow me to dial my SWG lower and keep the PH down as well. If you really want to avoid buying the largest SWG to get near 3x I think it's totally feasible to use an inline chlorinator (cost usually under $100) to slowly feed in trichlor if needed to compensate for FC, lower PH and raise CYA.

-Tim

 

[Silver_2000]

Long term use of Trichlor is not recommended here due to raising CYA with every puck


"Trichlor contains 52% of cyanuric acid by weight, and contributes 0.6 ppm of cyanuric acid is added to the water, for each 1.0 ppm of Free Chlorine added."

 

[BasicTek]

Long term use of Trichlor is not recommended here due to raising CYA with every puck


"Trichlor contains 52% of cyanuric acid by weight, and contributes 0.6 ppm of cyanuric acid is added to the water, for each 1.0 ppm of Free Chlorine added."

when it's the only source of stabilizer and as the OP posted his SWG may not be the most oversized, with proper testing and control trichlor can be very beneficial

 

[Silver_2000]

when it's the only source of stabilizer and as the OP posted his SWG may not be the most oversized, with proper testing and control trichlor can be very beneficial

Since he hasn't yet purchased his SWG he is looking for recommendations.

And didn't mention having 100 lbs of Trichlor left over, I don't see the value in recommending an undersized SWG and supplementing with Trichlor. That again, as I stated ,and is one of the primary premises here and will cause the CYA to rise past recommended levels quickly. Then he will be stuck with an undersized SWG and CYA that can only be fixed by empty and refill or lots of rain.

But as should be assumed in EVERY post here. This is simply my opinion

 

[ping]

If you get the CircuPool get the RJ-60 or 60+ not the SJ. The cell design and extra features on the controller are well worth the extra money. The larger the cell size not only puts out more chlorine per day, it produces more chlorine over its lifespan compared to the smaller sized cells. If you wait, the site that you are looking at for CircuPool always has a sell going on. Right now they are trying to clear out some smaller sized cells, they usually have a free upgrade to the next larger sized cell.

The AutoPilot 52 sized cell will work fine also.

 

[Seadweller]

If you get the CircuPool get the RJ-60 or 60+ not the SJ. The cell design and extra features on the controller are well worth the extra money. The larger the cell size not only puts out more chlorine per day, it produces more chlorine over its lifespan compared to the smaller sized cells. If you wait, the site that you are looking at for CircuPool always has a sell going on. Right now they are trying to clear out some smaller sized cells, they usually have a free upgrade to the next larger sized cell.

The AutoPilot 52 sized cell will work fine also.

OK, I was going to pull the trigger on an RJ45 because it has the same chlorine output (2lbs/day) as the AutoPilot 52, but I guess I'll wait for a sale on the RJ60...I missed a brand new one on eBay a few days ago for $599, but had never heard of the brand so it was gone before I could research it. I was hoping to get away with the RJ45 because they're under $800 currently, and I'm not sure how much the RJ60 will come down from its current lofty price.

I guess the RJ60 can't hurt with the record heat we've had around here.

 

[Swampwoman]

This is just an opinion...my pool is actually 24k gallons (my sig is wrong, I should update that) and in your shoes if this is true:

For example, I could buy the 45K gallon unit on sale, and two additional replacement cells, for the same upfront cost as the 60K unit.

...then that's the one I'd get

My t-15 aquarite cell is rated for 1.45 lbs, which is roughly 7.2 ppm per day at 100% over 24 hrs. While with manual dosing I used about 2 ppm per day, ve found with swg I only need 1 - 1.5ish mst days (higher cya is why, I suspect, plus not as much wasted in burn off). So I'm well-covered even if I only ran pump 6 hrs. I have a variable speed pump and run longer, but you get the idea.

 

[SpringPool]

The previous sale was get the next model up for $20 more. So you’d pay the RJ-45 price plus 20.

Im hoping this comes back around at thanksgiving or early next year because I’ve decided on the RJ-60

 

[Seadweller]

If the RJ45 stays at $779, I'd be all over the RJ60 for $799 without a second thought. Problem is, will the RJ45 go back to its regular price of$1079? If that's the case then $1099 isn't much of a deal on the RJ60.

Decisions, decisions....

 

[SpringPool]

I believe it was the full price. Is $300 worth the extra cost? I think so because it will produce 3 lbs of Chlorine a day so I’m theory you shouldn’t have to run it as long and it will last longer.

 

[needsajet]

1. Over-sizing - I'm clear on this, for the most part, but....There's seems to be an "acceptable" range for over-sizing, which for my 25K gallon pool, would mean anywhere from a 40K to 60K system. I understand the concept of running the system at a fraction of it's output for longer service life, but there must be a point of diminishing returns.
- actually it's the contrary, bigger the cell, the cheaper it is, provided you run it for it's full lifespan, or nearly so

2. System Output - To make things more complicated, one system designed for a 60K gallon pool generates the same chlorine as another system designed for a 45K gallon pool. I spoke to the company that makes the 60K gallon system, and they said it would be more than perfect for my pool. It is rated for 2lbs per day, so does that mean any system rated at 2lbs per day would be sufficient, regardless of it's "up to XXX gallons" rating? Or, is there no common criteria for these measurements?
- forget the volume ratings, they're pure sales lingo and not meaningful - use lbs/day

3. Weighing Cost/Performance - The higher the output, the more expensive the system and replacement cell. For example, I could buy the 45K gallon unit on sale, and two additional replacement cells, for the same upfront cost as the 60K unit. At what point does over-sizing become cost prohibitive?
- if you move before it wears out

4. Adjustment Ranges - Some units allow finer adjustments, while others allow for adjustments in increments of 25%. I understand the benefit of finer adjustments, but how common is it that you'd be in between the ranges offered by a simpler system? From what I've read, the % adjustment merely controls the on/off cycle of the cell, which runs at 100% when it's on. What's the difference between operating the unit for 4 hours at 100%, or 12 hours at 25%? The cell is still operating at 100% for the same period of time, right?
- you'll probably need adjustment of 10%, especially if over-sized. only having 25/50/75/100 I think you'll end up running higher than you need to.

5. The Ultimate Decision - For a 25K gallon pool, does it make sense to over-size further to a unit that produces 3lbs/day, or is that overkill? It seems 2lbs/day should be more than sufficient for a 25K gallon pool, so what am I missing?
- if you'll be there for 7 or 8 years, there's every chance the bigger one will make the cheapest chlorine

This thread illustrates one method for comparing the economics between different sized cells, and you could do something similar with current prices: Economics of Saltwater Chlorine Generators