Acid use

[newfool]

I have had my pool a couple of years now, but I am still concerned with what I think is excessive acid usage. Every 3-4 days I need to add between 400-800ml of muriatic acid.
My chems tonight are:

Chlorine 2-4
pH 7.8
Total Alk 70
Cal Hardness 300

This is 4 days after I had the pool at 7.5pH, Chlorine at 10, Total alk at 80 with a cal hardness of 250 (I added some cal chloride to increase the hardness because the pool store kept giving me low readings) There has been no rain and I have lost about 1.25" due to evaporation, water temp 86-88 with ambient temps in the mid 90's

I had figured that by now I wouldn't need to add so much...your thoughts?

 

[257WbyMag]

What test kit are you using?

How old is your plaster?

 

[newfool]

The plaster is actually 3 years and a month old. Time flies... The test kit is a Taylor K-1004.

 

[anonapersona]

I find that at TA of 70 I actually get to *not* add acid every other day, so I am happy when my pool finally gets there. I know that in my case, it is because the tap water has a TA of 340 and so even a small topping off after evaporation adds to the TA level, which then makes the pH tend to rise rapidly.

The pool store is giving you advice based on what you'd need if you used trichlor pucks for daily chlorine. In that case your TA of 70 would be low, but they don't understand that with bleach we don't need to have that large a buffer.

 

[newfool]

I try to keep my TA at 80, it fluctuates up or down roughly 10 ppm but no more than that. I should have mentioned that yes I use liquid chlorine. I only use pucks if I am away or when I need to increase CYA.

 

[jasonknox]

I have to add acid quite regularly as well. I figured it was just the nature of the beast.
FC 7.5
CC 0
PH 7.5
CYA 45
TA 70/80

 

[Bama Rambler]

What happens if you don't adjust the pH when it gets to 7.8? does it stay there or does it keep going up?
If it stays at 7.8 then I'd leave it there. There are a lot of pools that like 7.8 pH and rarely go above it, but as soon as you aadjust it down it goes right back to 7.8.

 

[Speedo]

I need to check mine again tonight, I just added acid for the first time yesterday, heat wave has caused me to run my fountain all day. Prior to that, every time I checked it was always around 7.3-7.4.

After the heat wave things will change back. My TA is a bit high, so this is a good chance to get that taken care of.

This also reminds me, I need to test TA of my tap water.

 

[RobbieH]

Do you have any fountains, misters, anything like that?

 

[Beamup]

And just to make the point that it varies a lot between pools, my TA is 120 but it takes several weeks for the pH to go up from 7.2 to 7.8. So acid is more of a monthly thing for me. I count myself very lucky on that point.

 

[newfool]

No fountains, misters etc. I have never left it alone at 7.8 or 8.2 pH because of warranty issues and bacterial-static nature of lower pH.