Hello, I've been away for awhile but recently got a new "portable" spa. Holds about 200 gallons of water. I had a question about start up/new fill I couldn't find the answer to. My tap water is a bit acidic but when I start with a new fill the pH goes up to over 8.4 while heating up, I'm assuming due to aeration. It takes about 18 hours to heat the tub (110V) and the jets are on low the whole time to heat the water raising thus raising the pH. I've figured out how much dry acid to use to get the tub in the 7.6 range. I'm wondering if I can add the dry acid when the tub is cold and the water is still acidic so that it will be balance when the tub is hot after the start up process. I'm using the Dichlor/Bleach method for sanitation. What I would like to do is add calcium, baking soda, dry acid and dichlor as soon as the tub is filled and cold so I can use it the next night when its heated up and have the water balanced. Currently I am adding calcium, baking soda and dichlor as soon as the tub is filled cold and then adjust the pH after it is warmed up and the pH has gone up due to aeration. But now I know how much dry acid I need to get it to where it needs to be when the tub water is hot and hoping to add it in when it is cold before it is heated up. My concern might be that the water will be too acidic with a big load of dry acid put in before the aeration has had a chance to increase the pH. Any thoughts?
New fill pH question
- Thread starter anojones
- Start date
Read the sticky pinned to the top of the forum, add muriatic acid instead of dry acid, but don't add anything except maybe enough dichlor to bring fc to maybe 10 ppm initially.
PH can read falsely high with a drop test, is that how you tested your PH?
Also, read the sticky...
Did I mention the sticky?
PH can read falsely high with a drop test, is that how you tested your PH?
Also, read the sticky...
Did I mention the sticky?
Thanks for the help. I’ve been a little leery of the muriatic acid but probably should bite the bullet. I’ve been using test strips but have a Taylor kit on the way. The sticky is fantastic thanks again
Don't let the muriatic scare you. It will make marks instantly in concrete but you'll hardly notice it on yourself if you happen to spill or get drops/runs on your skin. Don't let it sit for too long obviously but unlike liquid chlorine, it rinses off immediately and easily. We just dunk our hands in the water and jiggle it to wash it off.
- Jun 1, 2018
- 13,770
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
To answer your question(s):
*Can you adjust ph in while the water is cold? Sure, if it needs it.
We do it in pools most all the time.
*Should you add acid to lower the ph in advance before it rises? NO
The ph should remain in the 7’s at all times - preemptively dosing risks tanking ph & ta .
Also, ph & ta are married chemically. Aeration is the only way to change one without affecting the other- ph rises, ta stays the same.
Any chemical you add that lowers one will lower the other, any chem you add that increases one will increase the other in some way.
The higher the ta, the faster the ph rise.
No need for baking soda unless ta is below 50. You’re just creating an endless merry go round doing that whilst also adding acid.
*Please note that dichlor is also acidic & lowers ph & subsequently ta so take that into consideration before also dosing with acid.
Use
PoolMath effects of adding to see its effects on your water & to calculate additions.
*Can you adjust ph in while the water is cold? Sure, if it needs it.
We do it in pools most all the time.
*Should you add acid to lower the ph in advance before it rises? NO
The ph should remain in the 7’s at all times - preemptively dosing risks tanking ph & ta .
Also, ph & ta are married chemically. Aeration is the only way to change one without affecting the other- ph rises, ta stays the same.
Any chemical you add that lowers one will lower the other, any chem you add that increases one will increase the other in some way.
The higher the ta, the faster the ph rise.
No need for baking soda unless ta is below 50. You’re just creating an endless merry go round doing that whilst also adding acid.
*Please note that dichlor is also acidic & lowers ph & subsequently ta so take that into consideration before also dosing with acid.
Use
PoolMath effects of adding to see its effects on your water & to calculate additions.
Appreciate it, getting things figured out after getting the Taylor kit. It looks like for the next start up I'll probably have to get the pH down once it's warmed up and just then get the alkalinity right with some baking soda. Got it balance now but the very high pH threw me off for awhile.
I dumped about two cups of MA onto my brick pavers the other day by accident. They started to foam up red. I got a bucked and washed the MA off. It was in contact for about a minute or two. End results, barely even cleaned the brick, and did nothing to the moss between the bricks.
Be careful with it - yes, especially not in the eyes, or breathing in it. But is not as if it is hydrofluoric acid.