Water Balance for SWGs

jodyeslinger · Jul 15, 2013

Hello. I am new to trouble free pool and owning a swg system. My pool is an 18X48 soft side with sand filter that is a fresh total fill with city tap water. I added cell saver and pool start 3 - n-1 ( which adds cya to the water) upon opening the pool. I then added 60 pounds of pool salt per the manufacturer instructions. The pool has been open 2 weeks now and is crystal clear but I have a few issues and questions. My FC level is reading 0 despite adding cya twice and running my swg system on two boost cycles and regular 8 hr cycles daily. MY cya reading is 10. The ph is 8, alkalinity 220 and salt level is 3200. I have added muriatic acid twice in the past week. 1 quart the first time and 2 quarts today to hopefully lower alkalinity and ph. I have had traditional chlorine pools for years and am familiar with fixing these issues in a traditional chlorine pool but not a saltwater pool. Do I need to add chlorine until I get the issues resolved? And is there anything I need to do that I am not doing to resolve my chemistry issues? Any and all help/advice would be GREATLY appreciated!

linen · Jul 15, 2013

Welcome to tfp, jodyeslinger :wave:

Have you seen this pool school document?: http://www.troublefreepool.com/pool-school/water_balance_saltwater_generator

What do you plates look like? Are they clean or are there deposits on them?

chiefwej · Jul 15, 2013

Yes, add chlorine, regular bleach is fine. The SWG is designed to maintain the FC level but it can be a challenge for it to get it up there. CYA can take a week or sometimes even more to show up in water tests. If you are sure you added enough to get yours to the proper level, DO NOT ADD MORE. You will have to drain water, if you get it too high. Once a CYA level of around 30-40 shows up in the water it will start holding chlorine levels, until then you should use bleach or liquid chlorine to keep the levels up.

jodyeslinger · Jul 15, 2013

My plates/cells are brand new as is my swg system. I am concerned about my cya level getting to high. But the local pool store that tested my water suggested I add more today as it has been 2 weeks since first dose and only registers 10. I have added approx 2 pnds out of a 4 pnd bag of hth 3n1, 1 pnd at start up and 1 pnd today. Also how much bleach do you recommend and should I continue to run swg on regular cycle daily or continue to use boost cycle to help build FCC level. Thank you for your quick response and help.

linen · Jul 15, 2013

How does your water look?

2 lbs of the the hth 3 in 1 (which is 75% cya and 25% stuff we don't typically recommend) will raise your 5700 gallon pool (I am assuming your water level is 36 inches) by 32 ppm cya. Assuming you have added no other stabilizer or trichor (often a puck), or dichlor (often labeled as powdered "shock")...then that is all the cya that should be in there. We recommend 70-80 ppm cya.

For 32 ppm cya we would recommend using bleach/liquid chlorine to get the FC up to 3 ppm, then have the swg take over and keep the FC up above 2 ppm at all times. Once you get your cya up to 70 ppm then you should keep your FC above 3 ppm.

Please read this pool school article as well: http://www.troublefreepool.com/pool-school/pool_water_chemistry

chiefwej · Jul 15, 2013

1. Add all the info about our pool to your signature. That will help give people the info (pool capacity, pump size, type of filter, ect.) that they need to answer your questions.

2. Learn to use the http://www.poolcalculator.com/. It will help you determine just what to do and how much of anything you should add.

3. Spend a bit of time reading Pool School. It's the upper right button on this screen.

Aquatica · Jul 15, 2013

your cya is too low. if you added it via the skimmer it would go into the filter and dissolve fast. Like within 48hrs (run pump 24/7) you should have a reading. cya needs to be 60-80

also pump run time affects fc level. maybe increase that for a few days to get fc level up. I like to run pumps 24/7 until fc is where I want it.

I would drop TA down to 70-80 where it will stop pH from jumping back up high. You can do this very quickly. drop pH down to 7.2 with acid and then wait for it to climb back up to 8.0 then drop it back down again. keep doing this until it starts to stay around 7.5-7.6

I like it around there and then it drifts up over time to 7.8 I target 7.8 with swg's as it allows me to add cya when needed and the cya drops the pH down a little. Then pH over time goes back up to 7.8 and then when we need to top up cya levels we again are controlling pH using the cya top ups. won't need to be adding acid to control pH. Let the cya do that. but you have to get TA down to 70-80 first.

Also if your fill water is high in TA it will raise your pH so you will need to add acid. I had our clients switch from using well water which was high in TA to city water which was low in TA..around 30ppm in city and 300ppm in wells. When we started charging for acid they started filling with low TA water. topping up water levels was really only necessary mainly during our dry months. but this used to cost us a ton of money in unnecessary acid.