New pebble finish - Adding acid every day?

dgb99

0
Jun 17, 2011
9
Plano, TX
I have an issue similar to a recent post about quickly rising pH. I didn't want to piggyback but I'm obviously paying attention to any responses to that thread as well.

Here are my numbers from this morning's final test with my TF-100 kit:
FC 6.5
CC 0
TC 6.5
pH 7.4
TA 75
CH 270
CYA 45
Temp 87

No problem, right? However, this was after testing earlier in the morning and applying my daily or at least every other daily dose of bleach and muriatic acid per the poolcalculator.com (bleach and acid added ~20 minutes apart, testing done 30 minutes later).

Here are my results from two days ago 7/30 (same time of morning) after balancing the water and then from this morning before adding chems:

FC 8 -> 2
CC 0 -> 0
TC 8 -> 2
pH 7.4 -> 8.1
TA 80 -> did not test early morning
CH 270 -> did not test early morning
CYA 45 -> 45
Temp 89 -> 87

My pool story:
We recently had a complete pool renovation done. The pool is about 16 years old and had the original plain white plaster. We've been in the house for ~8 years. My previous method of maintaining the chems in the pool was to use 3in tablets in a floating chlorinator and indiscriminately throw 1 bag of 'shock' every other week. I used Leslie's tabs and either Leslie's Power Powder Plus or their 4in1 (or is it 3in1?) powder for the shock. I wasn't picky about what I used for the shock (bought on sale) although I was somewhat aware that each one did add either cyanuric acid or calcium which would eventually mean I would need to drain the pool. About 5 years ago, we started having issues with yellow algae. After doing at least 3 'pool store recommended' treatments with lots of shock and YellowOut (which were successful at keeping the yellow algae away for about 1.5 months), I started using PhosFree (again, on recommendation from the pool store to keep the yellow algae from coming back). I'd pour one capful a week (6oz?) into the skimmer.

To be honest, contrary to all I've read on this site now, I had ~5 years of absolutely no issues with pool chemistry which made me think the pool store's recommendations weren't so bad. The chemicals I did add were not terribly expensive given the amounts I needed (yes, PhosFree is expensive but I would buy on sale and only used a capful per week). I'd test CL every other week and might have to open or close the floating chlorinator a bit based on the results. I'd test ph, and Alk once or twice a month and they never moved much at all. I long for those days...

Fast forward to now....all pool equipment and plaster/tile/coping have been replaced. Plain white plaster has been replaced with Riverbend Sandler's (local pool builder...not sure if they are national) 'riversand' product which I believe is equivalent or similar to PebbleTec's pebblesheen (basically a pebble surface but smaller pebbles). I figured I ought to learn how to take care of the new plaster which lead me to troublefreepool.com and the wealth of information here (as well as getting a TF-100 kit). I definitely like the idea of keeping it simple and inexpensive (BBB method) but so far it has been anything but that...

Reading pool school and these forums, I have been pretty much beaten into submission about the idea that I am going to have to add bleach pretty much every day if I want to keep using bleach as a sanitizer. I might be ok with that if I didn't also need to add acid almost every day and baking soda 1-2 times a week to keep ph and Alkalinity in check.

I am aware that new plaster will cause pH to rise but I'm just not sure if adding acid every day is normal. And of course adding acid every day is causing my alkalinity to creep lower so I end up adding baking soda 1-2 times a week. I am testing the water between 1-3 times a day just to keep up with To be fair, I am quite paranoid about screwing up the new finish or the new pool equipment so I am probably going overboard with the testing. But is this frequent addition of acid and baking soda normal?

I've been reading on the other threads about pH rise being caused by too high of alkalinity and that alkalinity will find some kind of sweet spot. But how low is too low for alkalinity?

Two other items of note
1. I mentioned the new pool equipment above because the returns in my spa (combo pool/spa) seem bubblier than they used to be which might be affecting my pH.
2. I have three returns in the pool (and four in the spa). I installed 2 PVC 'pool coolers' this weekend and ran them for ~24 hours and blocked the third return (spa jets unchanged). I assume the pool coolers/fountains will also affect pH although the data above is representative of what I had before they were put in as well. Even if it does cause pH to rise faster, it is worth it as it lowered the pool temp by at least 5 degrees which makes swimming much more enjoyable. Pretty impressive!

Also, couple of questions about testing:
1. Where should I collect the sample?
For years, I have been sticking the bottle down at the return which allows the bottle to fill up quite quickly. However, the sample bottle I recently got from the pool renovation company's supply store has a note on it to collect from 12-18 in deep away from the returns. So I've started doing that (collecting away from returns), this does seem to affect the sample somewhat (mostly alkalinity).
2. When dropping multiple drops from the test kit bottles, does it matter if I drop 10 drops at a time versus 1 drop at time?
It seems to make a fair difference in the results. For example, if I have a pretty good idea that my CL is going to be close to 8 based on what I recently put in, I might drop 14 drops of the R-0871 FAS/DPD bottle, swirl, and then drop one drop at a time until the solution turns clear. By experimentation, it seems that I can be 'off' by almost 1.5 ppm CL depending on if I drop/swirl/drop every drop vs. dropping a large amount at one time. This obviously applies for other tests like the CH test where you always drop 20 drops of the R-0010. It wouldn't make sense to me in that case to drop/swirl/drop each time but please let me know the 'correct' way.

Sorry for the long-winded first post. I've been doing a lot of reading but am looking for confirmation that I'm on the right track...
 
My luna quartz (supposed to be similar to pebblesheen) surface required a huge amount of acid during the first month to six weeks. I used 4 gallons the first week alone.

It's now 8 months later and I'm still using about a gallon a week of MA to keep pH below 8.0-8.2. My SWG, oversized pump and spillover spa all contribute to the need for the MA. I'm trying to get TA down to 60 or so, but it's slow going.
 
Hmmm...interesting results today testing again after ~14 hours (with the pump running).

So I had the usual CL loss of about 3 (actually measured 4.5 from 8).

However, pH measured 7.5 (from 7.4 this morning). Obviously a lot smaller jump than in previous testing (even if I extrapolate for 24 or 48 hours). One explanation might be that installation of the pool coolers involved removing the three eyeball return covers. Today, the pool coolers were removed but I did not put the eyeball returns back in. The end result being (for whatever reason) a lot less aeration. Even the spa returns (which still have the eyeball in place) are bubbling a lot less. Now I do have some concern about how not having the eyeballs in place is affecting my overall circulation but given that I'm running the pump for 12 hours, I'm not too worried.

I'm still hoping someone can provide comment on this as well as some of my testing questions.
 
When you say your returns are "bubblier" than usual, do you mean there are air bubbles coming out of the returns or that they're disturbing the surface causing bubbles?

If you actually have air bubbles coming out of the returns, there's a lot of your problem. That much aeration will definitely cause your pH to rise. That, along with the new plaster will cause a lot of rise.

Now to your testing question. The reason many of us recommend getting the SpeedStir is that it makes testing so much easier and more precise.
The best method is to swirl as you drop each drop. Regardless of which test you're doing.

You should be taking the sample away from the returns about elbow deep. You should also rinse the sample bottle twice in the pool before taking the sample.
 
Yes, with all eyeball return covers in place, the four returns in the spa have bubbles coming out and the three returns in the pool occasionally have bubbles (although not nearly as much as the spa). Before the renovation (with all eyeball return covers in place), it was less bubbly but there was definitely some bubbles in the spa. I'm not sure why my pH didn't rise back then.

I removed all three eyeball return covers in the pool to install the poolcoolers so, for the day yesterday, there was just a straight 2in (or whatever size) opening at each return. Almost no bubbles out of any return and the surface of the water is so smooth it is hard to tell whether the pump is even on from inside the house.

I lowered the pH to ~7.3 last night to see if I can get away with not adding acid for at least 2 days. We'll see.

I am considering getting the speedstir although that would fuel my wife's thoughts that I am over-concerned with testing the water. ;) When you use the speedstir, do you need to somehow account for the volume of the magnetic bar or is it small enough to not make a difference?

Thanks for your answers.
 
It sounds like you have a suction leak that's letting air into the system. Your pool returns shouldn't have bubbles in them. Your spa should only have them if the blower is on or they have air injection nozzles.
 
Hmmm...I have always been concerned that my main drain didn't have full suction. But, to be clear, without the fittings installed now, I have barely any bubbles on any of the returns (maybe a few on the spa returns which may be air injection nozzles). How would I know if they are air injection nozzles? Maybe I'll try to take some pictures with the eyeball fittings installed in the main pool and without them and post them here. Thanks again!
 
There is no control to change any airflow to the spa jets as far as I know. The return flow is controlled by an actuator/valve that diverts some of the water to the main pool return and some to the spa (set about 70% main/30% spa in pool mode). In spa mode, the actuator turns to 100% spa, 0% main.

I will try to get some pictures up this weekend (if nothing else, to show off my sparkly BBB water...). However, for now, I've been keeping the pool coolers running to see how low a temperature I can get (lowest so far is 83!). This is continuing to contribute to pH rise.

So, how low is too low for total alkalinity?

I saw previous comments that alkalinity will find a happy place and generally stay there. However, with additional acid needed to counter the new plaster and the aeration caused by the pool coolers, I figure I will eventually need to counteract with some baking soda. Right now, I'd say the TA is between 60 and 70. The sixth drop definitely turns the sample completely pink and the seventh drop causes an ever-so-slightly more vibrant shade of pink. Eighth drop does nothing.
 

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Thanks! I'm not ready just yet to go to the 50 ppm borates (which I guess means my water is really BBB'd?). I'm going to see how things go over the next few months without the borates so that I have something to compare to later. My water looks/feels fine right now and I've got the routine down to where I have a pretty good idea of what I need to add each day and only need to test every 2nd or 3rd day. Eventually, I'd like to get to a point to where I only need to test the water twice a week (assuming normal swimming time and weather).
 
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