Reverse Osmosis Fill Water Due to High TA?

[cdwells]

I just ordered a CORE-55 and am converting to SWG. After tons of reading, I have noticed many with complaints of SWG raising pH more quickly than desired.

My problem is going to be that I already have to add 32oz of 31.45 Muriatic acid for every two inches of fill water to reduce the excessively high TA of my municipality (1,069 gal/2 inches @ 225 TA).

Once I switch to SWG, I am going to target a TA much closer to the bottom of the range, which will mean even more acid.

I’ve performed a few different searches but can’t find any articles/posts discussing this as a solution, they’re mostly related to filtering out CYA/CH as an alternative to replacement.

I am now curious if anyone has any information or thoughts on a household RO filter for fill water to essentially zero out minerals and reduce me dependency on acid.

I know they’re low output, but if plumbed in properly, they can (mostly) keep up even with the scorching central Oklahoma summers.

Even if the money is equal to or slightly more than the cost of HCl, the reduced need to birddog the balance might just be worth it.

Am I on to something here, or totally off my rocker?

 

[ajw22]

I think @mknauss uses a portable RV RO filter for his pool fill water.

 

[PoolStored]

SWG raising pH more quickly than desired.

This is not true.

pH rise with SWG

Sorry to belabor, but this has been really bugging me, the seemingly contradictory data from various TFP experts. Chem Geek clearly states "The hydrogen gas bubbles out of the returns and aerates the water and is the main cause of pH rise in SWG pools." I see those very bubbles. They are...

www.troublefreepool.com

 

[mknauss]

I have an RV Water Softener for my pool. It is manually regenerated. I would not use RO, you waste about a third of the water using RO and the filters are pretty expensive.

 

[Bperry]

I just ordered a CORE-55 and am converting to SWG. After tons of reading, I have noticed many with complaints of SWG raising pH more quickly than desired.

My problem is going to be that I already have to add 32oz of 31.45 Muriatic acid for every two inches of fill water to reduce the excessively high TA of my municipality (1,069 gal/2 inches @ 225 TA).

Once I switch to SWG, I am going to target a TA much closer to the bottom of the range, which will mean even more acid.

I’ve performed a few different searches but can’t find any articles/posts discussing this as a solution, they’re mostly related to filtering out CYA/CH as an alternative to replacement.

I am now curious if anyone has any information or thoughts on a household RO filter for fill water to essentially zero out minerals and reduce me dependency on acid.

I know they’re low output, but if plumbed in properly, they can (mostly) keep up even with the scorching central Oklahoma summers.

Even if the money is equal to or slightly more than the cost of HCl, the reduced need to birddog the balance might just be worth it.

Am I on to something here, or totally off my rocker?

If you are using trichlor pucks to chlorinate right now, there will be a slight pH trend upward if you stop using them because they are acidic and tend to hold down the pH a bit. This trend has nothing to do with the salt chlorinator though.

If you’ve already been using liquid chlorine like TFP recommends, then there won’t be any difference in pH rise.

If you’de like to slow the pH rise and you have any water features that aerate the water, turning them off or running them less per day will help.

 

[JoyfulNoise]

Point of Use RO systems, even good ones, are horribly inefficient. The lesser quality ones will generate as much as 3 gallons of waste water to produce 1 gallon of RO water. That would be a very costly and wasteful in your case.

You’re only realistic option is to reduce evaporation loss which is what drives your fill water additions. If you cover your pool, you’ll use a lot less fill water.

 

[cdwells]

This is not true.

pH rise with SWG

Sorry to belabor, but this has been really bugging me, the seemingly contradictory data from various TFP experts. Chem Geek clearly states "The hydrogen gas bubbles out of the returns and aerates the water and is the main cause of pH rise in SWG pools." I see those very bubbles. They are...

www.troublefreepool.com

I read that entire thread and many more prior to posting this. Unless I missed something, the end of that conversation pretty much ended in a stalemate, as have many others. I understand the chemical reaction is net neutral, but there is at least SOMETHING that drives up pH for many folks, quite a few of whom I can tell are intelligent and trying to sort it out.

I don’t even have my SWG installed yet, I am mostly trying to be prepared for what may come when I do, in addition to trying to reduce my dependency on HCl.

 

[cdwells]

I have an RV Water Softener for my pool. It is manually regenerated. I would not use RO, you waste about a third of the water using RO and the filters are pretty expensive.

Hi! Thanks for taking the time to reply!

To clarify, are you using yours for a drain/refill alternative, (re)fill water, or both?

I am only interested in using one for (re)fill during the hottest part of the summer when I am losing an inch a day to evaporation.

Edit: just noticed you said you’re using a softener, not RO. I fill w/soft water myself to help keep my other levels I check. I sure wish it worked on TA!

 

[cdwells]

If you are using trichlor pucks to chlorinate right now, there will be a slight pH trend upward if you stop using them because they are acidic and tend to hold down the pH a bit. This trend has nothing to do with the salt chlorinator though.

If you’ve already been using liquid chlorine like TFP recommends, then there won’t be any difference in pH rise.

If you’de like to slow the pH rise and you have any water features that aerate the water, turning them off or running them less per day will help.

I am using LC, and only throw in pucks when I am going to be absent for a few days or when I need a slight maintenance bump in CYA.

I do understand what you’re saying though, and could be the reason why many people see that rise after switching from tricolor pucks to SWG.

 

[cdwells]

Point of Use RO systems, even good ones, are horribly inefficient. The lesser quality ones will generate as much as 3 gallons of waste water to produce 1 gallon of RO water. That would be a very costly and wasteful in your case.

You’re only realistic option is to reduce evaporation loss which is what drives your fill water additions. If you cover your pool, you’ll use a lot less fill water.

Thanks for your input! You are most likely spot on. I may just have to rely on HCl from now on, as covering for most of the year is not an option for our family (daily use, moderate swimmer load, 33’ diameter pool and typically short on manpower, etc.).

 

[mknauss]

Edit: just noticed you said you’re using a softener, not RO. I fill w/soft water myself to help keep my other levels I check. I sure wish it worked on TA!

I would just add the acid to lower the TA when needed. If you control the CH rise with the soft water, a little higher TA is no big deal.

 

[cdwells]

I would just add the acid to lower the TA when needed. If you control the CH rise with the soft water, a little higher TA is no big deal.

This seems to be the general consensus. The lab geek in me will only let me change one variable at a time anyhow, which will first be the SWG. If I still have problems afterward then I may consider other options. Thanks again!

 

[pjt]

I also have very high TA fill water (330). I try to harvest rainwater and minimize adding fill water. I also allow my water level to fluctuate ±1.5" from design waterline to allow mother nature to fill my pool.

Targeting a TA of 50-60 will dramatically slow pH rise. My acid demand is ~1 gallon/month.

 

[cdwells]

I also have very high TA fill water (330). I try to harvest rainwater and minimize adding fill water. I also allow my water level to fluctuate ±1.5" from design waterline to allow mother nature to fill my pool.

Targeting a TA of 50-60 will dramatically slow pH rise. My acid demand is ~1 gallon/month.

We just got a good rain today and my level came up about 2”, which was a godsend.

Mind if I ask how you harvest your rainwater?

 

[pjt]

Mind if I ask how you harvest your rainwater?

I modified my overflow so that I can fill my pool ~1.5" above the design waterline. I also delay filling my pool until the level is ~1" below the design waterline. This avoids sending water down the drainpipe and also minimizes the amount of fill water I need. When it rains, my pool can take as much rainwater as possible. I'm also installing downspout diverters to add additional rainwater to the pool instead of wasting it to the storm drain.

 

[JoyfulNoise]

Here in the desert we use 500 to 1000 gallon (or larger) water storage tanks. We in the roof gutters into 3” PVC pipe and divert roof water into the tanks. Many homes are constructed with flat roofs around here so even an inch of rain can equal hundreds or a thousand plus gallons of water. As long as the top of the tank is lower than the roof line, you can place a tank pretty much anywhere on the property and run the PVC buried in the ground to it. A friend of ours has a big 1,200 gallon tank in the corner of her lot and the main section of her roof gutter runs into PVC that goes below grade and then daylights by the tank. She easily fills the tank with every rainstorm we get and her tank has an irrigation pump and controller on it. She waters her garden and some landscaping with the captured water.

 

[cdwells]

I modified my overflow so that I can fill my pool ~1.5" above the design waterline. I also delay filling my pool until the level is ~1" below the design waterline. This avoids sending water down the drainpipe and also minimizes the amount of fill water I need. When it rains, my pool can take as much rainwater as possible. I'm also installing downspout diverters to add additional rainwater to the pool instead of wasting it to the storm drain.

Awesome ideas. Thanks!