New SWG pool owner - FC=0

[ChristianK]

Hi,

We just purchased a house with a vinyl lined pool. The dimensions are 16 ft * 32 ft. I haven't done all the math about the volume, but it 7 ft 8" at the deep end and 3 ft at the shallow end. The previous owner had installed a SWG (BLSC40-C), and said that he ran the pump 24*7. He said that the pool hasn't needed any chemicals, but he used to bring a sample to a pool store. The dial on the SWG controller was set to 32% output. the "Check cell" light is flashing. It reports a salinity of 3.5.

We have been happily using the pool for the past few weeks, adding water every 3-4 days because it has been >90 F for most of the time. I changed the pool timer to run 8-9 hrs/day, since running 24*7 seems excessive. I ordered the "TF-Pro Salt with SmartStir", but hadn't gotten around to testing yet. Today I noticed some green algae growing along the bottom edge of the pool. I ran the dolphin yesterday and it had lots of green stuff in the filter.

So I finally opened up the test kit tonight, and ran the FAS/DPD test. I added 1 heaping scoop of R-0870 with the smart-stirrer running (light on), but didn't see any color change. I added 2 more scoops and it stayed completely clear. I then used the comparator block, and I could not detect any yellow color, suggesting that I might have no FC. The PH was around 7.8. After a while the water in the FAS/DPD test did turn pink, but that was 10+ minutes after I had added the powder, so I ignored that.

I turned the pump on to run full time now, and just set the SWG output to 100%. I turned the switch to "Super Chlor", but the corresponding LED did not come on.
Is there anything else I should do? Which other tests are important at this point? I'm a bit overwhelmed by the number of possible tests.
How long should I wait before running the FAS/DPD test again?
What should I do about the flashing "Check Cell" light?
Is the pool unsafe to swim in?

Thanks so much

Christian

 

[PoolStored]

Christian, welcome to TFP...you came to the right place!

Your first order of business is the ALGAE. To fix this, you will need to SLAM. Read this -->SLAM Process
To do the SLAM process correctly, we need to know your pH and your CYA. Do these tests first. Really, no other tests matter.
The CYA test is really important. Follow the instructions here:

Extended Test Kit Directions Archives

www.troublefreepool.com

Basically what we are going to do is to raise the chlorine level in your pool to a level that will kill the algae. Before we do that we need to get your pH to 7.2-7.4, and your CYA to about 30 (40/50/60 are ok too). However to guide you on how much liquid chlorine to add, we need to know pH and CYA.

To your cell throwing a flashing "Check cell" light, that means the cell needs to be cleaned or it has failed. Do you have the brand and model number of the controller (the box that controls the cell, not the cell). That would help us.

 

[ChristianK]

Thanks, I will measure my CYA tomorrow. I posted a picture in the previous message of the "comparator" test, which showed pH around 7.8. Should I do a different test to figure out pH level? I also got the digital pH tester, is that more accurate? I guess I'll have to get some Muriatic Acid first to get my pH down.

The controller for my SWG is a Blueworks BLH Series, I found the manual and it suggests the flashing "Check cell" light means it needs to be inspected after 300 hours, a solid light indicates problems.

 

[wireform]

The short answer is no chlorine is a disaster waiting tho happen meaning algae taking hold. The fact you can't measure FC can be several possibilities, a) algae consuming it, b)CYA possibly off the charts, c) SWCG not putting out. First order of the day is to check CYA level and since you'll need to slam bring the PH down to 7.2 or there about. Salt water cells are maintainers once the needed level holds but it can't bring up the FC from zero.

 

[YippeeSkippy]

You need Liquid Chlorine in there TODAY! SWGs work too slowly to bring your chlorine up faster than algae can have a *party with many bad choices made* (Algae reproduces like bunnies).

I would add a full gallon of 10-12% Liquid Chlorine and let the pump and SWG continue on and test in 30 min or so. Tell us whatcha get.

Maddie

 

[YippeeSkippy]

I estimate your pool volume at ~20,000 gallons.

 

[ChristianK]

I just checked my CYA and it seems to be <30. I have the tube that is labeled 30 at the top, and I can clearly see the dot when it is filled to that level. I filled the mixing bottle to 7.5 ml with pool water (85F) and then added 0013 until the 15 ml mark. Shook it for 30-45 seconds, and it stayed completely clear. See pictures below.

I calculated the volume of the pool at 15,200 gallons. My PH was 7.8 last night. Should I first get the PH down with 4.6 oZ of 31.45% muriatic acid? Or is adding chlorine the highest priority?
How about HDX 81 oz. Laundry Disinfecting Bleach from Home Depot?
I thought I needed to get the PH to 7.2 before starting the SLAM, do I also need to do something about the low CYA?. I assume the best place to bet muriatic acid is the pool store, Home Depot only has the weaker version.

Thanks

 

[mknauss]

Should I first get the PH down with 4.6 oZ of 31.45% muriatic acid? Or is adding chlorine the highest priority?
How about HDX 81 oz. Laundry Disinfecting Bleach from Home Depot?
I thought I needed to get the PH to 7.2 before starting the SLAM, do I also need to do something about the low CYA?.

Add chlorine. Add the acid. 15 minutes apart.
Start dissolving the CYA granules. Target 30 ppm CYA.
That bleach is likely weak and expensive. Check the pool area in the Garden section. Or Ocean State Job Lots. Many of those in NJ. They are a good source for your pool chemical needs.

 

[PoolStored]

I just checked my CYA and it seems to be <30. I have the tube that is labeled 30 at the top, and I can clearly see the dot when it is filled to that level. I filled the mixing bottle to 7.5 ml with pool water (85F) and then added 0013 until the 15 ml mark. Shook it for 30-45 seconds, and it stayed completely clear. See pictures below.

I calculated the volume of the pool at 15,200 gallons. My PH was 7.8 last night. Should I first get the PH down with 4.6 oZ of 31.45% muriatic acid? Or is adding chlorine the highest priority?
How about HDX 81 oz. Laundry Disinfecting Bleach from Home Depot?
I thought I needed to get the PH to 7.2 before starting the SLAM, do I also need to do something about the low CYA?. I assume the best place to bet muriatic acid is the pool store, Home Depot only has the weaker version.

Thanks

I would say that you have no CYA. I would get dry stabilizer, put it in a sock and put it in your skimmer. After about 1/2 hour it will soften and you can squeeze away (kinda fun) to get it dissolved. You can also hang in front of a return. Use pool math and your 15,200 gallons to determine how much to put in.

At the same time, lower your pH to 7.2 or so, then we are on to SLAM.

Use the 30ppm CYA as your slam level, which would be 12.

You can use this, it is available in 4pack for 17 in Milltown, NJ HomeDepot. Aisle 58, Bay 013 

Pool Essentials Pool Chlorinating Liquid (4-Pack) 26489355392 - The Home Depot

Pool Essentials Chlorinating Liquid is used for everyday swimming pool water sanitization. This easy to use liquid chlorine pool chemical effectively cleans pool water and kills bacteria. The fast acting

www.homedepot.com

You can use this MA, also available in Milltown, Aisle 63, Bay 002 

HDX 1 Gal. Muriatic Acid (2-Pack) pH Adjuster 10031HDX - The Home Depot

HDX 1 Gal. Muriatic Acid (2-Pack) is a powerful pH reducer for your swimming pool. It comes ready to use, with no pre-mixing required. This fast-working chemical helps prevent scaling caused by calcium-based

www.homedepot.com

 

[ChristianK]

Thanks both to PoolStored and mknauss for the quick and super helpful responses. Didn't know about Ocean State Job Lots.
According to PoolMath I need 3 lbs 13 oz of dry stabilizer to get my CYA from 0 to 30. Seems like it would take a while (and a very large sock) to get 3.5 lbs of dry stabilizer disolved. I'm thinking of buying this 7 lbs Chlorine Stabilizer:


And for my FC, to get to a SLAM level of 12: I need 187 oz of 12.5% Bleach, I'm thinking of buying 2 jugs of this (or will I need more to maintain the SLAM?):


Not sure if they also sell Muriatic Acid. I think I need 4.6 oz of 31.45% muriatic acid, or 9.3 oz of 15.7%. The Home Depot link is for 2 * 1 gallon, which I think is 29%, and would be way more than I need. Hopefully Ocean State Job Lots has smaller quantities Muriatic Acid.

On my way to the store, thanks again for all your help.

Christian

 

[PoolStored]

Thanks both to PoolStored and mknauss for the quick and super helpful responses. Didn't know about Ocean State Job Lots.
According to PoolMath I need 3 lbs 13 oz of dry stabilizer to get my CYA from 0 to 30. Seems like it would take a while (and a very large sock) to get 3.5 lbs of dry stabilizer disolved. I'm thinking of buying this 7 lbs Chlorine Stabilizer:

Get the DRY stabilizer. Liquid is problematic for a number of reasons. I can get about 2lbs per sock, so just do two socks!

And for my FC, to get to a SLAM level of 12: I need 187 oz of 12.5% Bleach, I'm thinking of buying 2 jugs of this (or will I need more to maintain the SLAM?):

You will likely need more. My 30K pool took about 40 gallons. I'd probably get 10-15 to start. You can always take it back (ask me how I know).

Not sure if they also sell Muriatic Acid. I think I need 4.6 oz of 31.45% muriatic acid, or 9.3 oz of 15.7%. The Home Depot link is for 2 * 1 gallon, which I think is 29%, and would be way more than I need. Hopefully Ocean State Job Lots has smaller quantities Muriatic Acid.

Yeah, but I'd get a gallon. You may experience rising pH, as many pool owners do, you will need the MA.

On my way to the store, thanks again for all your help.

Christian

Your welcome, good luck.

 

[mknauss]

Thanks both to PoolStored and mknauss for the quick and super helpful responses.

You are welcome -- I am sure things will start going your way.

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[ChristianK]

I just wanted to give a quick update, and ask another question.

I seem to have completed my SLAM, FC was 7 at 10pm last night and still 7 at 8:45am. CC=0 and the water is clear. The dolphin did not have any green stuff in its filter.

I had turned off my SWG during the SLAM process, and turned it back on this morning and set it for 50% output. I hadn't checked my salinity ever, so I finally got around to that today. My reading was 1400 ppm (7 drops of R-0718). That seems incredibly low. My SWG is reporting 3.2 grams/liter. I'm wondering if this is why my FC had gone to zero, and it also makes me wonder if I have a leak. I just had to add 330 gallons to my 16*32 pool after 4 days.

I assume I need to add a ton of salt to make my SWG happy. I saw previous recommendations for Splash Ready salt from Home Depot. I didn't see a salt calculator in the PoolMath app, how much do I need?

Details:
Since Sunday I've added a total of 3 gallon jugs of 12.5% Chlorine. 7 oz of 20% Muriatic Acid and 61 oz of dry stabilizer. My stabilizer was pretty much fully dissolved from the socks in the skimmer by Tuesday morning. I checked it this morning (Wednesday) and the CYA is still below 30, I can still see the dot fairly clearly at a full tube (30). I haven't checked pH since I understand that is unreliable during SLAM'ing.

 

[PoolStored]

I just wanted to give a quick update, and ask another question.

I seem to have completed my SLAM, FC was 7 at 10pm last night and still 7 at 8:45am. CC=0 and the water is clear. The dolphin did not have any green stuff in its filter.

I had turned off my SWG during the SLAM process, and turned it back on this morning and set it for 50% output. I hadn't checked my salinity ever, so I finally got around to that today. My reading was 1400 ppm (7 drops of R-0718). That seems incredibly low. My SWG is reporting 3.2 grams/liter. I'm wondering if this is why my FC had gone to zero, and it also makes me wonder if I have a leak. I just had to add 330 gallons to my 16*32 pool after 4 days.

Likely the reason. 330 gallons will not effect your salt level.

I assume I need to add a ton of salt to make my SWG happy. I saw previous recommendations for Splash Ready salt from Home Depot. I didn't see a salt calculator in the PoolMath app, how much do I need?

If there is no salt on your home screen, click on the gear in upper right, then scroll down and enable "track salt." Then you can add your 1400 result as a "log test." 1400 should show up on home screen. Now, click salt from home screen, enter your target salt it will tell you how much to add.

Details:
Since Sunday I've added a total of 3 gallon jugs of 12.5% Chlorine. 7 oz of 20% Muriatic Acid and 61 oz of dry stabilizer. My stabilizer was pretty much fully dissolved from the socks in the skimmer by Tuesday morning. I checked it this morning (Wednesday) and the CYA is still below 30, I can still see the dot fairly clearly at a full tube (30). I haven't checked pH since I understand that is unreliable during SLAM'ing.

I might test CYA Again. I would shake gently (don't want to make lots of bubbles). I would wait a minute and shake again before testing. Sometimes it takes a while to precipitate. Make sure you are OUTSIDE with BRIGHT sunlight at your back when you are testing. Lighting makes a HUGE difference...

 

[Deb04]

If you bought the AquaMate dry CYA at Ocean State, that could be why your CYA hasn’t increased. I tried using that stuff for about two years and it took at least two to three times as much to get to the levels I needed. I guess I’m a slow learner. I get my CYA at Amazon or Walmart now.

Ocean States liquid chlorine is great. CYA, not so much.