My pS234 test results

[Watermom]

You can't drain a pool down too far or you may have it pop out of the ground if you have a high water table. Thus, the need to do several smaller drains instead of one big one.

[CarlD]

Since your T/A is 200ppm in a F/G pool, I think you are close to done on that--anything under 180ppm you should be OK.

A CYA of 40 or 50 is great--you'll use less chlorine but it won't break down in sunlight.

TDS is nonsense 99% of the time (every SWG owner has TDS that's "too high").

And, of course, phosphates is the latest scare tactic. Only worry about phosphates when our cleanup methods don't work.

I think you are doing great!

[lskeate]

Pool still looks great. It's not chewing through the chlorine. But I still have a couple of questions. When "Watermom" tells me to slowly add muriatic acid, what is slowly? A quart, half gallon, gallon? The pool store printout wants me to add 3 gallons!

"Carl" says I'm almost there. If I get my ALK down to 150-180, am I still aiming for a Ph of 7.5-7.7?

Also, some people mention the pool's exposure to the sun. I live in west Texas where the sun is always shining and my pool is in the sun for the majority of daylight hours. What if I keep a bubble cover on the pool when we aren't using it? Does that help stabilize your chlorine? Once I figure out the exact amount of bleach to maintain the desired chlorine level, is it going to require more as the water gets warmer?

As always, I appreciate you moderators and your vast knowledge of pools and chemistry. I was an accounting major which helps balance the checkbook but not chemicals.

[waterbear]

Since your T/A is 200ppm in a F/G pool, I think you are close to done on that--anything under 180ppm you should be OK.

Sorry to disagree with you on this one Carl but if the pool is being chlorinated iwth bleach there will be much better pH stability and less acid demand if the TA is more like 70-90 ppm. I have seen this time and again with my customers using liquid chorine or with SWGs and now recommend it as a matter of course. I also apply this to my own fiberglass pool.

On the other hand, if the pool is being chlorinated with (gasp!) trichlor or dichlor, then a TA up to 180 ppm is probably OK but under 150 would be better. (I preper to keep it between 100-120 ppm).

(I know you weren't sleeping through all the discussions Chemgeek and I had about outgassing of CO2!)

[CarlD]

Since Evan sees firsthand F/G pools, I'd tend to take his advice first. In vinyl pools, I've seen t/a of 180 with no problems.

As for muriatic acid, "slow" usually means a cup to a quart pour VERY slowly into the return stream. Better still is to pour it SLOWLY into a 5 gallon bucket of water, then pour THAT into the return stream--less chance of stray acid reaching the pool wall.

3 gallons????!!!??? Maybe if your pH was 9.5 in a 48,000 gallon pool and you wanted to make it into an acid wash! Pool stores! Feh!


We believe in slow and gradual for all chemicals other than chlorine. If your pH is still in the 8's I'd add about 1/2 quart of muriatic acid and wait 12 hours, then check pH again. That's because you have 20K gallons and your pH is very high. Otherwise, I'd suggest half that--1 cup.

[waterbear]

Since Evan sees firsthand F/G pools, I'd tend to take his advice first. In vinyl pools, I've seen t/a of 180 with no problems.
It applies to vinyl also. However, many AGPs don't have as much aeration from the returns and don't have water features compared to IG so there is less aeraton so they can get away with higher TA without major pH problems. However, lowering the TA will still contribute to pH stability. It's the basic chemistry involved!
As for muriatic acid, "slow" usually means a cup to a quart pour VERY slowly into the return stream. Better still is to pour it SLOWLY into a 5 gallon bucket of water, then pour THAT into the return stream--less chance of stray acid reaching the pool wall.

3 gallons????!!!??? Maybe if your pH was 9.5 in a 48,000 gallon pool and you wanted to make it into an acid wash! Pool stores! Feh!
This amount is what would be needed to lower the TA ,not for pH adjustment, BUT I wold not put it all in at once. I would follow the sticky on how to lower TA. This is around the total amount of acid that would be needed to do it.
Adding acid lowers TA, aeration brings the pH back up without causing the TA to go up again.

We believe in slow and gradual for all chemicals other than chlorine. If your pH is still in the 8's I'd add about 1/2 quart of muriatic acid and wait 12 hours, then check pH again. That's because you have 20K gallons and your pH is very high. Otherwise, I'd suggest half that--1 cup.

Until the TA is lowered the pH is going to be moving toward 8.0 fast and the acid consumption will be high.

[PhantomAndy]

You can't drain a pool down too far or you may have it pop out of the ground if you have a high water table. Thus, the need to do several smaller drains instead of one big one.

You can float the liner in vinyl pools as well. The rule of thumb with virtually all pool types is no more than 1 foot below the skimmer.

My water table is so high I never go more than a hair below the return lines (about 4 inches below skimmer level). We have a high water table here and even that's risky enough.