SWG Operation - Lessons Learned

[SeanB.]

Our construction hasn't begun yet but our PB told us during our design session that we would use a chlorine floater for the first 10 days after filling the pool and then start up our swg. It will be a gunite pool with plaster. Is 10 days long enough, or should we wait longer?

Thanks.

[PatL34]

Sean, Welcome to the forum.

I would wait longer. At least a month.

Unless your PB has prescribed what you should use in the floater, I would use a combination of regular unscented bleach and trichlor pucks. The pucks will add stabilizer (CYA) until you get to a 60 - 80 ppm level of CYA, and then use bleach exclusively.

Add muriatic acid ONLY to maintain pH at 7.2 - 7.6, and monitor the TA until it gets to about 80 ppm. Then adjust the return jets upwards to maintain that TA level while you are still curing, as it will help to keep the TA down and the curing.

The calcium hardness (CH) will rise naturally as the gunite is curing, so if you have the ability to use water that is no more than 200 ppm CH as initial fill I would do so. If you have to use well water, which I do NOT recommend, then a temporay filter that has the ability to remove metals and CH, HAS to be inserted in the delivery line.

BTW, make sure that there will be no sand in the gunite mix, as this can lead to pitting of the gunite at low pH as it is curing.

Hope this helps with your deliberations with your PB, and good luck.

Pat

[PatL34]

Hi Pat

You say that I may want to lower SWCG from 50% I assume to extend it's life, but then I'd need to circ longer thus more power, guess it's a trade off.

The function of the SWCG is to generate chlorine, but in so doing, scale tends to build up on the cell membranes. This is removed by reversing the polarity to the membranes, and for this to work properly, the SWCG has to run at least 2 reversals to keep the membranes clear. Check with your manual for the default reversal settings, (usually 4 hours each, total 8) or call your SWCG vendor for more information on this.

Keep pH in 7.2-7.6 so don't think that's why etching.

Similar to you, pool builder added salt about 1 month after plaster & fill.

Thanks for ideas . . . cheers.

Hope this helps.

Pat

[Poolsean]

Pat, please, no offense intended by commenting on your responses.

Sean - regarding floating a tab feeder. There really is no reason that you can't start the Salt system up right away, with the exception of if the plaster manufacturer can void warranty if you do not wait a certain period of time. This point of view varies widely among the pool plasters.
I would be cautious with floating a tablet feeder, as it will tend to float and stick to one corner of your pool. Erosion of the tablets will also tend to fall out of the feeder and onto the plaster, where it has the potential to cause problems. Perhaps tethering it to a handrail or ladder rail, towards the deep end, rather than by the steps, where it will be even closer to the plaster.

KEEP AN EYE ON YOUR pH LEVEL!! This will cause more problems than anything else. Allow it to drift up, you will end up with calcium stalagmites all over your pool surface.



Per your suggestion to Katy, it's best to check with the manufacturer.

Pool Pilot has the ability to remember where it was in the forward or reverse polarity cycle when the pump shuts off. That way, when it starts back up, it will continue operating in the same direction so as not to cause uneven cell wear. This allows YOU to control how many hours per day you want to run your pump.

As MOST systems don't have this memory, your suggestion of even run times would be correct...but according to the specific Salt Chlorine Generator manufacturer. Everyone's reversal rates are different.
ie, Aquarite reverses every 100 minutes...therefore a run time in 200 minute increments (ie; 200 minutes (3 hrs 20 minutes pump run time - which I can't imagine anyone doing) / 400 minutes (6 hrs 40 minutes - more reasonable) /600 minutes (10 hrs - ahhhh, that's where the 10 hr pump run time comes from!) would ensure even cell wear.

Hope this helps.

[steveinaz]

Thanks for this thread, great info for pool-newbies like myself.

[Spensar]

Very interesting. Are there considerations for winter storage in the North with several months of below freezing temperatures?

On Ebay I see there are several for $500 to $700. Any particular brand recommended? I saw Hayward Aquarite, The Pool Thing, Zodiac and Pentair for sale in that range.

Any caveats or raves or are they all about the same? Does one use the cell up quicker? Warranty and service support issues?

[PatL34]

I have revised the intial post on this thread, to reflect discussions I had with Chem_Geek regarding the SWCG process.

The main difference is that the pH does not rise. It stays steady. This is the anomaly I saw with members mentioning this with liner pools. However with plaster pools the continuous leaching of calcium hydroxide, will raise the pH and so muriatic acid is needed accordingly. My apologies for any confusion this might have caused.

Pat

[waterbear]

I have a fiberglass pool and have experienced a pH rise with my SWG. It is slow (and even slower now that I have 50 ppm borates in the water) but it is still happening.

[PatL34]

Evan,

I suspect that there might be a slight loss of Cl that is not protected by the CYA, even though Richard (Chem_Geek) describes the SWCG operation somewhat as a "closed System". Ex-chemical engineers don't believe in "closed systems".

As Richard has mentioned, there are a lot of loose ends regarding the SWCG process that still need to be tied up. Your experience of rising pH is just one.

Pat

[bbb]

Are there considerations for winter storage in the North with several months of below freezing temperatures?

Good question. I just closed my pool in the Northeast, and it's my first year with the Autopilot. 2 questions:

1) Do any of you bring your cell manifold assembly inside for the winter?

and

2) Since I have the Autopilot control assembly in my shed, I would not be able to bring the cables inside. How would I winterize the cables if I remove the cell manifold assembly (I was thinking in tightly sealed plastic bags)