SWG with Sunearth EP-40 Solar Panels

[Vandergraff]

I am considering adding a SWG to chlorinate the pool (currently I use liquid chlorine) but am a little concerned about whether they could cause issues with the Sunearth EP-40 Panels I use to the heat the pool

As you can see from the panel specs they have copper internal piping and I wonder if the salt could cause corrosion or disolve built up 'scale' in the panels which might be protecting any potential leaks. The panels are now 23+ years old and are going strong.

When I asked the installer of the panels he advised against a SWG and recommended staying with liquid chlorine. He says he has other customers with these panels that were installed in 1981 and use liquid chlorine and still going strong.

I know the salt water levels here are relatively low at around 3,000 ppm (vs sea water around 35,000 ppm).

Does anyone else have experience with these type of panels and a SWG - or thoughts about running a SWG with this type of panel.

Thanks

 

[Oly]

I would suggest getting a sodium chloride test kit Taylor K-1766 and testing your pool water, you may be surprised what your levels are currently.
After 3+ years of a full drain and using only liquid chlorine my NaCl levels were well north of 4K ppm. I had to lower my pool water salt levels before starting my SWG.

 

[Vandergraff]

Thanks for the suggestion - I will do that and see what my salt levels are and post back here. If they are already 3000 ppm+ I guess I shouldn't have an issue.

However reading 'Water Balance for SWGs' in the Pool School I may have another issue with Total Alkalinity - I will start another thread on that.

 

[mknauss]

I will start another thread on that.

Keep your questions here. Better to have all in one spot.

 

[Vandergraff]

Per my other post I am considering adding a SWG to chlorinate the pool (currently I use liquid chlorine) however when reading 'Water Balance for SWGs' in the Pool School I saw this 'Adjust your Total Alkalinity to 60-80 ppm. (This is IMPORTANT!)'

This will be an issue for me. My fill water is well water with high alkalinity and I have long since given to trying to keep TA in the suggested but focus on keeping PH within the suggested range. Typically my TA is 150+ but if I keep PH and Chlorine in the recommended range the water is clear and feels good in the pool

If I have TA of 150+ but can keep PH in the suggested range in the Water Balance for SWGs' in the Pool School will that be OK for a SWG?

Thanks

 

[Vandergraff]

Sorry I thought I should keep solar panel questions and TA question separate?

 

[mknauss]

The reason controlling TA with a SWCG is important is that a high TA exacerbates the scaling of the SWCG plates. If you can keep the pH in the mid 7's, though that tends to be quite difficult with high TA, you should be OK. What is the normal CH of the pool water?

The use of borates in the water may also help.

 

[Vandergraff]

CH about 300

We check chlorine and PH daily and adjust daily using liquid chlorine and muratic acid and Pool Math - so generally can keep within recommended levels although PH is definitely a challenge to keep within the recommended levels

(still think it would be easier to separate the question about salt level with copper panels and TA levels into different threads - they are different topics with different answers and audiences)

Thanks

 

[mknauss]

What is your fill water TA? It is normally easier to lower the TA of the bulk fill water and then manage the pH which will naturally manage the TA. This will protect the solar panels (pH is the only threat to them, salt has no effect).

 

[Vandergraff]

TA of the fill water is 470 (a lot of drops of R-009!). Testing in the holding tank where the water is treated with a Triple-O Ozone WATER treatment system system.

How would I treat the bulk fill water before it goes to the pool?

I am not concerned with TA / PH for the solar panels - as I said above the panels were installed in 1998 and are still going strong with 23 years of this water.

I am concerned what effect salt would have on these panels - I am pretty sure salt water will corrode the copper piping inside these Sunearth EP-40 Panels - the only question is what salt level would be an issue.

Based on the 'Water Balance for SWGs' article in the Pool School I am also concerned what effect the TA might have on a SWG if I have one installed. As above the TA in the pool is normally ~ 150+ but I can manage to keep PH in the suggested range in the Water Balance for SWGs article.

 

[mknauss]

Salt water does not corrode the copper heat exchanger in pool heaters. So why would it corrode the copper heat exchanger in your solar panels.

You use acid to lower TA.

I agree, if you try to run a SWCG with very high TA, it will be problematic. Borates may help as they keep the pH rise in the SWCG cell to a minimum.

 

[Vandergraff]

I understand acid is used to lower TA what I didn't understand was how to lower the fill water TA.

When I fill the pool I normally have water running into the pool through a fill line for about 45 minutes - how would I practically use acid to lower that much water as it runs into the pool.

Above you had said 'It is normally easier to lower the TA of the bulk fill water'

(I also measured the PH of the fill water it is about 7.8 while the TA is 470).

Thanks

 

[mknauss]

Sorry, should be bulk 'pool' water.

That is some very high TA water. First I have seen in California.

 

[Vandergraff]

OK I understand.

It is well water

I have found regular adding of water with this high TA makes it very hard to get the TA in the suggested range. That's why I focus on keeping PH in the suggested range.

Maybe I will try to adjust pool TA this year - by keeping lowering PH to the bottom of the suggested range and see if I can get there.

I just need to be careful because I definitely don't want low PH water going through the copper in the solar panels

 

[Vandergraff]

A few more questions as I wait to see if I can keep TA /PH in the recommended range and test current salt levels.

We run the pool pump for around 8 hours a day - basically running in the summer for hours when the solar is heating. Our pool is ~20,000 gallons so I am assuming we should be looking at Pentair IC60 (8 hours is 1/3 24 and 60 is 3 times 20,000 rating). Pentair because we have a SunTouch Controller although it sounds like other SWG may be better than Pentair....

When we got a quote for installation the installer was suggesting the IC40 and measured for that. Are the IC40 and IC60 same physical dimensions - I am struggling to find IC60 dimensions online. The SWG will be installed vertically and I want to make sure it will fit.

Page 5 of the Pentair manual says 'The IntelliChlor® SCG is designed to operate with water flow rates from 25 +/- 5 gallons per minute (gpm)' - that's good for when the Solar is running as Flow rate is ~26 gpm with clean filter. We don't know the flow rate when solar isn't running - the flow rate meters are on the solar pipes. When solar is off we have set the pump run at much slower speed.

What do people do for chlorination in the winter. Here in Central CA we turn the solar off from Oct - April and pool temps drop into low 50s. Page 16 of the Pentair manual says 'The IntelliChlorSCG switches off and will not produce chlorine in water temperatures of 52° F, ±3° F'. I have read elsewhere that you should shut off the SWG at temps below 60F.

Thanks

 

[mknauss]

Are the IC40 and IC60 same physical dimensions

Yes. They are interchangeable.

The SWG will be installed vertically and I want to make sure it will fit.

The cell, if installed vertically, must be installed in an upward flow configuration. This is due to the flow switch.

When solar is off we have set the pump run at much slower speed.

Every SWCG is a bit different. You will have to experiment at what RPM you will need to run the pump without solar to close the flow switch

What do people do for chlorination in the winter.

Use the SWCG until it will no longer create chlorine. Then add liquid chlorine as necessary (usually between every few days to a week or so). No issue running the SWCG at below 60F.

 

[Vandergraff]

The cell, if installed vertically, must be installed in an upward flow configuration. This is due to the flow switch.

Interesting - the way he was proposinbg to install the cell the flow would have been downwards. Doesn't inspire much confidence that he knows what he is doing

I checked the online owners manuel which does say 'Install IntelliChlor SCG cell vertically for best performance' but I couldn't find anywhere where it explicitly says it should be mounted in an upward flow configuration (the diagrams in the manual show upward flow but it doesn't say it must be upward). Can you point me to an online reference for this that I can use when discussing with the installer.

Thanks

 

[mknauss]

 

[Vandergraff]

I would suggest getting a sodium chloride test kit Taylor K-1766 and testing your pool water, you may be surprised what your levels are currently.
After 3+ years of a full drain and using only liquid chlorine my NaCl levels were well north of 4K ppm. I had to lower my pool water salt levels before starting my SWG.

I tested the pool today for salt and it is ~ 1900 ppm - so yes a bit salty but thankfully not over the limit for a SWG. Partially draining and filling the pool would be a nightmare - the well would take forever to refill and water delivery is VERY expensive here. It looks like I would just need to add a bit of salt.

A few other comments on TA/PH discussion above.

I lowed the PH to around 7.2 - but for last few days the pool has remained at PH 7.2 and TA 120 - I thought the PH would drift up the TA come down. I see suggestions to aerate the pool but I am not sure how I would do that. I don't have any water features etc.

 

[mknauss]

I see suggestions to aerate the pool but I am not sure how I would do that. I don't have any water features etc.

Wind across the surface is about all you would have with that type of pool.

Air compressor? Throw the hose in the pool for awhile?