Trichlor and Bleach usage in tandem

[Woodberg]

I've noticed that when I use Trichlor tablets, my PH tends to stay around 7.5-7.6. When I'm just using bleach as my chlorine source, my PH always wants to rise up to 7.8-8.0 so I'm always adding acid. I'm just curious why this happens. Looking at the pool calculator, I'm assuming this is why the recommended TA level is higher for a pool using Trichlor.

In my case, I'm trying a little experiement this spring using a combination of Bleach and Trichlor pucks. My theory is that I can use just enough Trichlor to keep the PH in check and supplement the additional chlorine needed with bleach. We get enough rain, that with bleach alone, my CYA level tends to drop over the course of the year. By using a combination of sources, I'm thinking it might stabilize my CYA also. I think I may have to raise my TA levels slightly to get everything stabile.

Any comments and has anyone else done this?

 

[Bama Rambler]

I don't know anybody else that haas done it but what you're doing is what we're all about. Testing and knowing what to do about the results. If you know that your CYA drops, and you know that your pH rises, then using tabs and liquid in tandem is a very good solution. By regular testing you can keep the CYA from getting too high.

 

[JasonLion]

You can almost always stop PH from rising when using straight bleach. Usually all it takes is lowering your TA a little.

 

[dmanb2b]

OK fellow mods, don't shoot me for saying this :bowdown: but I say, try it out Trichlor pucks are acidic, which is why it's keeping your TA in check. Using pucks alone is OK too during the wet season, but just keep an eye on CYA in those hot summer months and switch to liquid chlorine if CYA starts creeping up.

BBB is much more about knowing your water chemistry and how certain chemicals impact it than just using Bleach, Baking Soda and Borax....every pool is different. Your TA may be high, but if pucks are working, proceed with caution.

...Jason/Bama...sorry took to long to post...but...since I typed it...

 

[Woodberg]

You can almost always stop PH from rising when using straight bleach. Usually all it takes is lowering your TA a little.

My TA is currently at 60 and my PH still tends to rise. I've got a fair amount of aeration though, which is what I think it is. Any issues if I tried to lower it below 60?

 

[JasonLion]

Lowering TA below 60 is best only done when you are also using borates. You can lower TA to 50, especially with a SWG, but it starts to be low enough that PH swings start to be noticeable. Borates act in a very similar way to TA to keep the PH from swinging around, so when you are using borates you can lower TA further than you can when you aren't.

 

[frustratedpoolmom]

I ran my pool that way last summer. It's slightly more expensive route and it required more frequent monitoring on my behalf (because I was paranoid LOL) but it was fine. It's especially fine if you have a ton of tablets on hand already, or a cheap supplier of tablets and Borax/baking soda etc. don't use tablets from Walmart, they contain copper.

 

[chem geek]

Given that you've got water dilution that tends to keep the CYA in check when you use some Trichlor pucks, I don't see anything wrong with the combination approach you are proposing. Just note that if you are using a floating feeder for those pucks, that they can park themselves in one place and the high acidity can be damaging to pool surfaces, especially stainless steel that is in the water in that area. I speak from personal experience about this and am still living with some rusty mounts from using Trichlor pucks 8 years ago.

Just make sure to dial down the Trichlor pucks so that your CYA doesn't rise or rises slowly enough that you can tolerate it by raising the FC target proportionately.

 

[Woodberg]

I've got a puck feeder installed and I've dialed it down to 2 so they should dissolve slowly. We'll see how it goes.

 

[kirbinster]

I have done what you are suggesting for years. Bleach tends to raise my pH while pucks tend to drop it. Thus, I use one or two pucks a week in my 20x40 pool and use bleach for the rest of my chlorine needs. Doing this I have never had to add anything else to control pH.