Switching from Frog to SWCG

[PoolStored]

Since this thing has the ability to keep pool chlorinated at a setting of just 5% to 15%, bumping it to just 20% represents a full doubling of my average rate.

You need to look at the output for the period of time. The 20% for 4 hours will put .5FC in the pool.

My pool, 30K, with cover, 90 CYA will run 24/7 at 5-10% and has 1FC demand with no use.

Sunny day in July, I pull the cover and have many swimmers, my FC demand is 3.5-4.5. With lower CYA can get to 5.5FC demand. I turn the SWCG up to 50-70% when cover comes off, and back to 10% when cover goes on, or sometimes I wait until 8pm if cover goes on at 5-6. This typically handles any demand and leaves my FC close to starting FC.

If you turn your cell up to 50%, and run it for 8 hours, it will add 2.7FC. I would suggest that you try 50% running during the day/party. Better to be on the high side and avoid mins. If it is too much, raise it to 40% next time.

It is likely that that 20% is not enough, and your FC will fall.

 

[sande005]

Sidebar - put skimmer socks in the skimmers. And tomorrow, don't be surprised by the ball of dog hair in the deep end drain. Our well brushed guys seem to leave an awful lot in the pool....

 

[P00LNerd]

Thanks, guys! I just saw these last two messages, too late to follow them, but things held pretty well with SWG just bumped up to 20%

Pre-party: FC = 5.5 ppm
Post-party: FC = 5.0 ppm

These tests are all using the 10 mL sample, and my target range is 3.0 - 9.0 ppm.

I was hoping we'd land a little low anyway, so I could put some dichlor in the pool, wanting to get rid of this silly 2 lb. bottle the installers left. I also need a CYA boost, which dichlor does, albeit not much for 2 lb.

I'm not sure why TFP recommends a much higher CYA range for SWG than for LC, as I'd have thought the LC pools would benefit from more added stability, but I'm presently trying to get CYA from 55 ppm up to 75 ppm to be near middle of recommended range.

 

[PoolStored]

I'm not sure why TFP recommends a much higher CYA range for SWG than for LC

SWCG typically puts chlorine in all the time, so you can keep FC lower.
With LC, you typically add once a day, so have a higher starting point avoids getting to min..,

 

[P00LNerd]

Cool. Thanks! Since this 2 lb. of dichlor will really only raise my CYA a few points, I'll have to see what my local store has for CYA/stabilizer products, to get the rest of the way to middle of range.

 

[PoolStored]

Most CYA is CYA. Even the Clorox brand is fine. Just make sure it is 100% CYA. If the product is "XYZ," search for "XYZ SDS" on google to get the ingredients.

 

[proavia]

Don't dose based on CYA being 55 or being 75.
Round up to the next multiple of ten - 60 or 80.
Record as 60 or 80 or whatever multiple of 10.

If CYA reading is 51 to 59 count it as 60.

Being as it's almost August, you should be ok with CYA of 60 or 70 for the rest of the season - even if you use your heater into early fall in Pennsylvania.

 

[PoolStored]

Being as it's almost August, you should be ok with CYA of 60 or 70 for the rest of the season - even if you use your heater into early fall in Pennsylvania.

I have an alternate view, living up here. I maintain my cya all the way to closing. Saves a *bit* on the cell. Doesn't matter what level CYA I close the pool with, it is always below 20 when I open.

 

[proavia]

I have an alternate view, living up here. I maintain my cya all the way to closing. Saves a *bit* on the cell. Doesn't matter what level CYA I close the pool with, it is always below 20 when I open.

Possibly - but you can save a bit of money by not bumping the CYA if it's within 10 ppm of target range as well.
Neither view is wrong - just providing the OP with another alternative.

 

[PoolStored]

Possibly - but you can save a bit of money by not bumping the CYA if it's within 10 ppm of target range as well.
Neither view is wrong - just providing the OP with another alternative.

CYA is $3.50/lb.
1lb will raise CYA by about 10ppm in a 15K pool.
So, if I need 1-2lbs in Aug/Sep/Oct, then $3.50-$7.

Salt cell is $700.
Rated 15K hours. Assume 10K.
My annual usage is 500 hours.
Shoulder months, I run 5%, 24x7.
2.5 months (mid aug-oct), 5% = 90 hours of run time.
$700 / 10,000 is $.07 per hour.
90 x .07 = $6.30

I agree, I'd call it a wash, and not worth the time I took to calculate it.

 

[Newdude]

I'm not sure why TFP recommends a much higher CYA range for SWG than for LC, as I'd have thought the LC pools would benefit from more added stability

They totally would, but we are primarily teaching newbs and when they goof, their slam FC target is raised +4 for every 10 CYA.
If I was running LC with zero concerns of dancing the line at min (#teamrunhot) I would be using 60 or 70 CYA with bleach.

For SWG pools with chlorine being added slooooowly, the higher CYA is worth the risk for those learning.

 

[P00LNerd]

What’s the actual penalty of having low CYA in a SWG pool? It seems lower CYA = lower FC requirement, and thus less SWG demand = longer cell life.

Or does the CYA reduce burn-off by so much that it makes up for the higher demand? I’ve seen that burn-off does increase a bit with FC demand (I lose 3 ppm/day at 8 ppm, but maybe half that at 3 ppm, for the same CYA level.

 

[Newdude]

Or does the CYA reduce burn-off by so much that it makes up for the higher demand

Exactly that. It ends up a wash. At 60 to 90 CYA, my loss is the same whether I run a 5 or a 10 FC.

A great many of us realize our CYA dipped below SWG levels when we see a couple extra FC lost per day, constantly proving the theory.

 

[P00LNerd]

Figured I should come back and close the loop on what I did for the cord feed-thru:



Simple size #9 rubber stopper with hole, re-drilled to size of cord and slit with utility knife. Permanent, reusable system, for all of $10 and about 5 minutes of effort.