adjusting the SWCG - what's "normal"

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D

davelinde

0
Sep 18, 2012
391
Lake Nona, Florida
We have a new pool and got through starting up the SWCG fine - we added CYA, salt started the SWCG at 60% and immediately got chlorine. After some adjusting we were running it at a 20% duty cycle and maintaining the chlorine levels fine. Then many things changed at once:

1. Added more CYA to go from 40 to 60
2. It got warmer so the solar cover is off now
3. Numerous nieces, nephews and assorted others appeared and swimmer load went from none to many
4. Something must be leaking air into the solar array, so we get air bubbles out of the return all the time

So almost immediately the chlorine level dropped to undetectable and we turned up the duty cycle from 20 to 40, then 60, now 80% we are getting some chlorine back but it has not built to the target level yet - though it's only been a few days.

What's normal? I was running the pump 7 hours/day and bumped that up to 10 hours too. If I don't see chlorine build up soon I guess I should inspect the cell for deposits? I mentioned the extra air in the system but I am assuming that with high water flow the air over the cell is OK? I was just wondering what other see when trying to adjust the generator as things change.
 
I am having to adjust, also. A month ago, I started at 5 hrs a day, 50% SWG, & 30 CYA. Temps ranged from 48 to 60 then. Then I went to 65%. Last Saturday I checked and I had FC of .5. I dumped a jug of bleach in and changed my pump time to 9 hrs a day and turned on the super chlorinate feature. Later that day, I noticed the skimmers were not drawing hardly any water. I found the pump to be 26 psi instead of 15. I backwashed it and it looked like yellow mud from the pollen. I think the swg had shut off from low flow. Anyway, I put 8 lbs of CYA in and 25 lbs of CH and have my CYA up to 52. FC was 5 yesterday. I would like to run around 6 for safety, so I bumped mine up to 75% and still at 9 hours a day. Current water temp is 70°. I have the T15 cell installed last August. Last year in August and September, I was running it at 65% and maintaining a FC of 7. I wonder if the pollen is the problem and/or my cell needs cleaned also??
 
What is "normal" is having to adjust the SWG when there are changes in the pool.

When you lose too much FC it is best to raise the FC to your high end target with bleach right away. When I know there will be a large load on the pool, I raise my FC to 10ppm with my CYA at 70-80. I almost always get by with this and if there is a little cloudiness after the party I raise it right back up to 10ppm. My guess is that there is something growing in the pool now and the SWG is keeping it from blooming, but it can't get ahead of it. I suggest that you run an OCLT with the FC raised to 10 ppm or so. If it fails follow the shock process. Remember to turn off the SWG at least an hour before you take your night measurement.
 
There really is no "normal" for an SWG....it's whatever it takes to maintain your FC. If it's building, I would suggest adding bleach to get it where you need it, then dial it back down if it continues to increase.

The air is almost surely not coming from your solar because that's on the pressure side of your system. The air is coming from the suction side of your system between the skimmer(s) and the pump.
 
Like Ping said, do not rely on the SWG to raise the FC, use bleach. The SWG is better at maintaining than quickly raising.

SWG are not set and forget ... you still need to be testing often to ensure that the FC stays in range.

So the air is only when the solar is on correct? Is it all the time? Since the panels should drain at night, I get a LOT of air bubbling out in the morning and then there can be some smaller bubbles for awhile after that. Do you see air in the pump basket or in the filter?
 
duraleigh said:
The air is almost surely not coming from your solar because that's on the pressure side of your system. The air is coming from the suction side of your system between the skimmer(s) and the pump.
Click to expand...

The site glass on the suction has zero bubbles... the air coming out of the returns are huge bubbles... the lines coming off the roof are gurgling. I don't get it either - if not for the other evidence I'd agree with you...
 
OK... so I had to check what I've been assuming. I just flipped off the solar diverter valve and closed the service valves to isolate the roof. Bubbles stopped immediately. The only thing I can imagine is that the vacuum break is stuck open and letting air in? There is no (obvious) water coming off the roof, so nothing else is leaking out. The system always pushed air out when it kicks on and the array is purged - but now it is pushing air continuously. We have a call into the installer (it's new).
 
jblizzle said:
Like Ping said, do not rely on the SWG to raise the FC, use bleach. The SWG is better at maintaining than quickly raising.
SWG are not set and forget ... you still need to be testing often to ensure that the FC stays in range.
Click to expand...

I'll run it at 100% the rest of today and if the FC has not risen by tonight we'll get some chlorine.

I should probably pop it open soon too, just to be sure I don't have scale yet.

DW said she wanted to be the pool service and I've been telling her she needs to test daily... We are still getting the hang of it. For all the weeks before the swimmer load began it was a set/forget thing - so we are just learning. The good news is that this expensive toy is getting regular use - so I'm not complaining about doing the maintenance.
 

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duraleigh said:
Air does not get in to the pressure side....water leaks out.
Click to expand...

I saw this after I'd gone and checked it again. I'm not arguing with you btw... I completely agree, I cannot understand how anything on the roof is making suction. In fact - I posted this observation in my post about the SWCG not just because I wanted to know if air running over the cell could mess it up, but because I was half-way wondering if the cell could make that much gas that would look like air at the returns.

However that is not possible for two reasons... first, the air stops when I isolate the roof and second, the air primarily comes out of 3 returns and the first two are not fed by the SWCG.

odd. pondering.
 
So I've now experienced what I suppose the regulars here see often. Every morning I've been asking DW for the FC level and she kept saying "still really low" and "not changing"... I just went out to tell her we should test again now and go get chlorine and she had just come back from the pool store with chlorine. So we test (after she came back) and FC is 5... But we have chlorine now for when we need it.

I guess an OCLT is in order to see if it just took this much time to build or if it's going away each night.
 
When my solar system was new, a pebble got stuck in the vacuum breaker and was causing the system to suck air.

If you run on full speed, do the bubbles still return after a couple of minutes? It might be a speed issue.
 
Hopefully your solar installer will get to the bottom of this for you but since I just experienced something identical, I can tell you that the air bubbles in my solar panels were a symptom of air getting into the system through the skimmer (suction side). You might try making sure that your water level is topped off and that you don't have a stuck or missing weir door. Once those are addressed, you can release the air in your system through the cartridge filter and then build it back up sans air. I am not real experienced with pools but thought my .02c might be helpful since I went through this last week.
 
So I was just re-reading pool school stuff and I realized that we also got an inch of rain which could have impacted my FC too.
And, now reading how to shock I'm wondering how I get something to measure FC levels above 20? Our kit does ranges that top at 10... do I need a better kit or do I just calculate the shock level, dose it and assume?
 
To accurately measure FC you will need a FAS-DPD chlorine test. The FAS-DPD test will measure to 50 ppm and the accuracy is needed for the OCLT. You can not do the OCLT without this test. It is included in the TF100, but can also be bought as a separate test, see my signature for the link.
 
You want the FAS-DPD chlorine test ... it really is a must have as it take ALL the guess work out for determining FC and CC values:
http://tftestkits.net/FAS-DPD-Chlorine- ... t-p47.html

What kit do you currently have? How old is it? Where is it stored?
Just curious if getting a whole new kit (TF-100) might be a good idea. BTW, the SpeedStir makes the testing even easier.

How do you have 240 post and not know that ;)
 
ping said:
When my solar system was new, a pebble got stuck in the vacuum breaker and was causing the system to suck air.
If you run on full speed, do the bubbles still return after a couple of minutes? It might be a speed issue.
Click to expand...

If I crank up the speed (3250rpm) the air stops, when I drop it back (2500rpm) the air starts again. My outlet pressure (at filter) is 12 psi at 2500 and 20 psi at 3250 so my guess is that at the lower speed/pressure the far end of the array is not filling and I'm drawing suction through the vacuum break. It did not do this when new. So either my filter is dirtier or the vacuum break stopped sealing at low/no pressure?
 
jblizzle said:
You want the FAS-DPD chlorine test ... it really is a must have as it take ALL the guess work out for determining FC and CC values:
http://tftestkits.net/FAS-DPD-Chlorine- ... t-p47.html

What kit do you currently have? How old is it? Where is it stored?
Just curious if getting a whole new kit (TF-100) might be a good idea. BTW, the SpeedStir makes the testing even easier.

How do you have 240 post and not know that ;)
Click to expand...

Taylor K2005
The kit was ordered along with the equipment during the build - so that would be just about 4 months in my hands + time on their shelf.
We store it in the porch in a bin labeled "NOT FOR CHEMICAL STORAGE", next to the hot tub and with our other chemicals :).
I posted a lot of construction questions and up to now had left the chemistry to my wife.
 

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