Pool of the Rising PH

[swreeder70]

Greetings everyone,

Long time since I was last on this forum and since then, moved across the country and built a new pool

Our pool was completed in August 2015 and is a 15K Gallon IG, Pebble sheen pool with spa and water features. We previously had a 25K IG Vinyl and were located in PA before moving to TX.

With all that said, our pool has been eating acid like crazy. It was stable for the first six months of existence, requiring very little to keep things in check. The past four weeks have been a different story, where the PH is high every day. Usually takes 12-24oz of muratic acid to get it back in line only to have it high the following day. Our pool does get a good amount of aeration, so I am not sure if that combined with the new pool is causing it or what. Here is a look at our numbers from today (and this is pretty consistent)

PH - 8.0 (Acid demand 1 drop)
TA - 100
CYA - 30
FC - 3.0
CC - .4
CH - 210

Recently I've had the chrome on the pool lights get cloudy/scaly and also a big white crystal formed under my water feature that I had to chisel off. The stone wall is a waterfall as well as the stones on the beach entry.

 

[Texas Splash]

Holy smokes that is nice. I am jealous. Wow. Welcome to TFP! Yes, new plaster and the aeration combined with slightly elevated TA will all tend to pull pH up. Not much you can do about the aeration unless you slow down the spillover or bubblers, but for the TA you can let it continue to sink with the use of acid. Eventually you can let the TA go down to 60, maybe even try 50 and see how that works to help keep pH down. HERE's a good page for you.
- - - Updated - - -

Of course continue to watch the pH. 8 is high, so knock that down a bit - perhaps 7.3 or so then let the aeration bring it back up (that will help lower the TA as well). Can't tell how low your FC is at the moment without knowing your equipment. Do you have an SWG? Please add your pool info to your signature by going to the top of the TFP web page (just under the Pool School button) and select "SETTINGS". On the next page look to the left for a menu bar that says, “MY SETTINGS” and go to "EDIT SIGNATURE" to enter your pool and equipment info there. It will help us later. This link may also help you: Pool School - Read This BEFORE You Post.

Either way, your FC is a bit low, and your CC is creeping ever so close to .5 which indicates a possible problem. So let us know and we'll help some more. Have a great day.

 

[pooldv]

Welcome to TFP, nice pool!

Yep, bubblers and waterfalls aerate the water and raise the PH, run them less and the PH will rise less. And the TA needs to be lowered to 60 or 70. Pool School - Lower Total Alkalinity It is important to keep PH at 7.8 or lower.

Keep an eye on your CSI score in Poolmath and keep it slightly negative by tweaking your PH and TA, -0.1 to -0.2. This will eliminate potential for scaling. Pool School - Calcium Scaling

 

[swreeder70]

Thanks for the info. Owning a vinyl IG for 18 years and now moving to a different finish with water features is a big change. I've been using the TFP method for many years, so having some familiarity with it is a big help.

My TA was upwards of 130 and I have been reducing it with acid over the past two weeks. During the off season I've been keeping the FC between 3-4 and the water has been crystal clear. Signature updated with my info.

 

[swreeder70]

Signature included this time

 

[Richard320]

With that fountain and the spa drop, what you're describing is normal, even expected. When you adjust pH, push it down to 7.2. The lower pH speeds up the outgassing, which will cause pH to rise, which allows you to beat down the high TA. Once you get a couple days' breathing room from the pH rise, you're pretty much there. at that point you minimize the aeration.

I slipped the lid off a can of spray paint over the venturi air intake for my spa to reduce the air, and I also cut the flow to the spa.

I don't have a fountain, but I'd suggest you keep that off unless you need it for evaporative cooling later in the season or if you have guests to impress.

 

[demento]

How can you measure CC down to 0.4ppm? Isn't the resolution of the TF-100 test kit 0.5ppm?

 

[Richard320]

How can you measure CC down to 0.4ppm? Isn't the resolution of the TF-100 test kit 0.5ppm?

If you use a 25 ml sample, resolution is .2 per drop. That's what Taylor shows in their instructions--- you use up a lot more reagents that way!

Good catch, demento!

swreeder70, you can use a 10 ml sample and only one scoop of powder and multiply drops by .5 to save on reagents.

 

[swreeder70]

If you use a 25 ml sample, resolution is .2 per drop. That's what Taylor shows in their instructions--- you use up a lot more reagents that way!

Good catch, demento!

swreeder70, you can use a 10 ml sample and only one scoop of powder and multiply drops by .5 to save on reagents.

The directions say you still need two scoops of powder, only the reagents change from .2 to .5. Never understood why you still needed 2 scoops, so I always used the 25 ml sample.

 

[Richard320]

The directions say you still need two scoops of powder, only the reagents change from .2 to .5. Never understood why you still needed 2 scoops, so I always used the 25 ml sample.

Answer: So they can sell more refills.

One scoop is usually enough. After swirling but before adding drops, if you see any undissolved particles of the FAS-DPD powder, you have enough.

 

[swreeder70]

Thanks for the testing tip...I've now got a "tube is half full" outlook on it!


I also tweaked a few of my ball valves and run times.

Full scale waterfalls cut back to run once a day for 15 minutes (down from an hour per day). Will turn them on when being used going forward.
bubbler fountain cut off. Will keep it off unless someone is using the tanning deck
Spa spillover - Never given thought to tweaking the return flow to stop the spillover. That is something that i should have done in the off season.

Really will miss the sound of the live water features, but understand it is balance of aesthetics with additional maintenance vs less maintenance.

 

[Richard320]

Run everything full tilt until you have the TA down where you want it. It's sort of a ratcheting effect. pH is the ratchet wrench , TA is the nut. Acid turns the ratchet so pH and TA both move down. Then aeration lifts the ratchet. pH goes up. The nut -- the TA -- stays down. Repeat until pH holds or TA is to about 70, Then reduce the aeration.

You don't want to cut all the flow to the spa, lest it get stagnant. I've got mine throttled back so it's maybe ¼" deep coming out the spillway. On full flow, it's over 2" deep. It still makes plenty of noise.

 

[BuckeyeChris]

in that same vein, you do want to run the water features periodically to get fresh water in the pipes, to ensure proper chlorination wherever there is water. During the summer they'll be on enough, but during the winter, don't forget.

 

[swreeder70]

Run everything full tilt until you have the TA down where you want it. It's sort of a ratcheting effect. pH is the ratchet wrench , TA is the nut. Acid turns the ratchet so pH and TA both move down. Then aeration lifts the ratchet. pH goes up. The nut -- the TA -- stays down. Repeat until pH holds or TA is to about 70, Then reduce the aeration.

You don't want to cut all the flow to the spa, lest it get stagnant. I've got mine throttled back so it's maybe ¼" deep coming out the spillway. On full flow, it's over 2" deep. It still makes plenty of noise.

That TA nut is hard and slow to turn! Check the PH in the AM, its usually high (8.0) and requires 8-24oz to push it down to 7.2 and it will creep right back up by the next day. TA has been slowly dropping at 80 now.

 

[prs]

I had the same pH increase problem, but taking the TA down to 50 solved it. I found getting TA down was much faster if you added enough acid, via PoolMath, to take the pH down to 7.0.