Hello all and muratic acid question

My name is Bryan Barnard and I live in Nashville, Tn. I have been lurking around on this site for some time now, usually when I am having a problem with my pool, and I finally decided to sign up on the forum. I have a basic 18x40 rectangular shaped pool with a liner. Last summer I converted it over to a SWCG system and I also upgraded the pump to a variable speed Hayward pump.

My question is this: Since converting over to a SWCG system I continually have to monitor the ph levels because they always tend to go over 8. I normally use the ph lowering regent from Leslie's pools but over the weekend I decided to try using muriatic acid. Since this is my first time using muriatic acid is there any ratio that I need to keep in mind so that I do not lower the ph too much?

Thanks,
Bryan

Hi Bryan and welcome to the Pool Forum! Glad you decided to register and join us. What is the volume of your pool?

HI, and welcome to the forum!! Once you give the volume of your pool as Watermom requested, we can help you figure out how much to add. In the meantime, I wanted to warn you that you need to handle muriatic acid carefully--wear gloves, eye protection, and above all, stay upwind of the fumes. I can tell you from experience that one good whiff of the fumes from that stuff will make you seriously believe that you'll never breathe again. If it splashes on your skin, just dunk said skin in the pool to wash it off. If you splash it on concrete, even if you wash it, it will pit--so just be very, very careful.

Did Janet scare you enough? I hope so. Muriatic acid is dangerous stuff. It's cheaper, and once diluted, better for your pool, but it's dangerous.

On the other hand, it's not nearly as dangerous as gasoline, so it's not a big deal if you handle it correctly. Writing a muriatic acid page is on my to do list, but it will be a week or so. Three other tips you might want to keep in mind:

#1 - The fumes are bad to breath, but they are death on wiring. Do NOT leave even capped muriatic acid in your garage or pump room, unless it has EXCELLENT ventilation, like TWO open doors. Instead, store it outside in an old plastic garbage can or bucket. If you do store it inside, put it in a HD plastic trash bag, and close the bag tightly. When you need to use it, take the bottle and bag out TOGETHER, and open the bag outside.

#2 - Once you have opened the bottle, and removed the inner seal (sharp stainless kitchen knife -- RINSE blade promptly in pool) you can easily pour and avoid both fumes and splashes IF you will partially submerge the bottle in the pool, take the lid off and set it on the pool deck, and then tilt the bottle so that you pour into the pool with the bottle's lip only a few inches above the pool surface.

#3 - Guesstimate doses; do NOT try to measure them. If you try to measure acid, you WILL have bad fumes, and you WILL eventually spill some. Don't do this. Instead, figure out your approximate dose, and the pour about that amount or less directly from the original container. If in doubt, pour less: you can always add more later!

If you are having rising pH problems with your salt system a few things can help (since the main cause of pH rise in a salt pool is from outgassing of carbon dioxide):
1) make sure your CYA (stabilizer) is at the recommended maximum, usually 80 or 100 ppm. This will directly translate into less cell on time which translates into less aeration of the water from hydrogen gas generation in the cell which translates into less outgassing of CO2 which translates into slower pH rise.
2) lower your TA to around 70 ppm. TA is actually a measure of the bicarbonate (carbonation) in the water. We keep pools overcarbonated on purpose BUT the higher the TA (bicarbonates) the more CO2 that forms and the faster it outgasses. The faster it outgasses the faster the pH rises. High TA wants to push the pH to around 8.0 all the time.
3)When you lower the pool pH try not to drop it below 7.6 and when it gets higher than 7.8 drop it back down to 7.6 (this is actually easier than it sounds with a bit of practice and getting to know your pool AND having a good test kit like the Taylor K-2006). The lower we put the pH the faster it rises because the lower we put the pH we create more CO2 in the water from the bicarbonate in the water (if you are wondiering what I am talking about pour some vinegar on some baking soda).
4) adding borates to 50 ppm helps stabilize the pH around 7.6-7.7 for an extended period of time. There are commercial borate products on the market or you can use Borax (found in the laundry aisle) and muriatic acid to bring the borates up to 50 ppm.