New Salt System, algae is recurring regularly

[Watermom]

If you are going to put some trichlor in a floater, make sure your pH is in the high 7s to allow some wiggle room for it to drop while you are gone. Trichlor is very acidic.

[SunnyOptimism]

If you are going to put some trichlor in a floater, make sure your pH is in the high 7s to allow some wiggle room for it to drop while you are gone. Trichlor is very acidic.

Hi @Watermom!!

I just wanted to say that I have seen this warning a lot (in various context, not just from you) and I have to say that TriChlor pucks have never had any substantial effect on my pH. Now my pool water normally likes to rise in pH, I have an SWCG and a gunite pool so all those factors probably contribute to trichlor' lack of effect on my pH. Also, trichlor tabs take forever to dissolve in a float for me (typically 10-14 days for three 3" tablets to fully dissolve) so while the water locally around the float might be low pH, my pool water pH barely moves.

Truth be told, I rarely use pucks (only when my CYA needs to be bumped up) so I'm not regularly exposing my pool to trichlor.

Just thought I'd share my thoughts on the subject....

[CarlD]

Hi @Watermom!!

I just wanted to say that I have seen this warning a lot (in various context, not just from you) and I have to say that TriChlor pucks have never had any substantial effect on my pH. Now my pool water normally likes to rise in pH, I have an SWCG and a gunite pool so all those factors probably contribute to trichlor' lack of effect on my pH. Also, trichlor tabs take forever to dissolve in a float for me (typically 10-14 days for three 3" tablets to fully dissolve) so while the water locally around the float might be low pH, my pool water pH barely moves.

Truth be told, I rarely use pucks (only when my CYA needs to be bumped up) so I'm not regularly exposing my pool to trichlor.

Just thought I'd share my thoughts on the subject....

You have other factors acting to raise pH. Many people have a constant rising pH with SWCGs (I don't--don't know why). Many people also have rising pH while their masonry pool is curing. So all your tri-chlor was doing was offsetting some of the upward pressure on pH.

I went away once for 2 weeks (9 or 10 years ago) and left 4 floaters full of Trichlor tabs. When I came back, my CYA went from 30 to 70, my FC was about 5 or 6, but my pH had dropped below the measurable bottom of 6.8. 4 boxes of Borax later I was back in the 7's. At the time, here, there wasn't much discussion of the acidity of Tri-chlor tabs, merely of the additional stabilizer. So I asked the question and the answer came back: Tri-chlor is highly acidic.

[SunnyOptimism]

You have other factors acting to raise pH. Many people have a constant rising pH with SWCGs (I don't--don't know why). Many people also have rising pH while their masonry pool is curing. So all your tri-chlor was doing was offsetting some of the upward pressure on pH.

I went away once for 2 weeks (9 or 10 years ago) and left 4 floaters full of Trichlor tabs. When I came back, my CYA went from 30 to 70, my FC was about 5 or 6, but my pH had dropped below the measurable bottom of 6.8. 4 boxes of Borax later I was back in the 7's. At the time, here, there wasn't much discussion of the acidity of Tri-chlor tabs, merely of the additional stabilizer. So I asked the question and the answer came back: Tri-chlor is highly acidic.

The SWCG on balance is actually a pH neutral process. Initially, during the production of chlorine from salt, the chemical reactions raise the pH. But eventually, when that chlorine oxidizes organics or kills algae, those processes are inherently acidic. So on balance an SWCG pool should see no pH change. @chemgeek has some very extensive posts on the chemistry of the SWCG process.

But yes, trichlor is acidic and I have both borates and other factors that suppress the pH drop from that. I was just commenting because pH dropping from trichlor is not inherently an issue for me and I should be more cognizant to warn others about its acidity.

Wow, that's a crazy pH drop though!!

[CarlD]

Yeah, theoretically SWCGs are neutral. Theoretically. And I guess the theory works for me. But far too many of our members have experienced a rising pH from SWCGs to discount their experience. In fact, so many have had it happen it is the norm, and my non-rising pH is not the norm.

Just remember if your feet are getting frostbite and your hair is on fire, on average you're comfortable.

[kelemvor]

My swcg definitely increases pH as it operates. Regular doses of muriatic are on the menu in my pool. I presumed it was due to the bubbles and therefore co2 out-gassing that occurs when the swcg is in operation. My cell gave up the ghost this year and I ran the pool without the swcg. pH was stable the whole time.

http://www.poolforum.com/pf2/showthr...-in-SWCG-pools there's a post that talks about the phenomenon. I'm pretty sure I've seen chem geek write in detail about the process - but I can't find the thread right now.

[CarlD]

Your SWCG bubbles? How's that work? Doesn't it just feed into the return?
(Of course I understand that IF it bubbles, it's aerating and raising pH)

[kelemvor]

Your SWCG bubbles? How's that work? Doesn't it just feed into the return?
(Of course I understand that IF it bubbles, it's aerating and raising pH)

When the cell is energized, many small bubbles come out of the returns. They're easily visible. If you turn the cell off, no bubbles.

[CarlD]

When the cell is energized, many small bubbles come out of the returns. They're easily visible. If you turn the cell off, no bubbles.

Mine definitely does NOT do that! There must be some gasfication going on in the process.

[kelemvor]

Here's a little video. After it's been on for 15 minutes or so, there are far more bubbles than you see here. I turned it off so I could show off vs on and realized after taking 15 minutes of video that it would be VERY BORING to watch all of that.

The off/on cycle was to show that the bubbles weren't from a suction side leak.