Very High TA

[MrMeaner]

Ok.. long time pool owner but very neglectful pool maintainer. I am the type of person who likes to reasearch but it takes time and experience for stuff to sink in my tiny brain. A little back ground, build a new house late in 2008 with a new pool to go wiht it. I was very naive thinking if the pool was clear it was ok to swim in. I have never had a test kit( but have one on order -tk100) Anyhoo my brother who also has a salt water pool came by one day and explained some pool chemistry 101 to me. Other than running the salt water generator and using a little cholrine and/or shock here and there I have not done much else as far as testing or adding any other chemicals. I decided i needed to get edjumacated on pool chemisty before I really do some damage to the pool and/or my kids swimming in it. I decided to take some water up to Leslie Pool and have it tested.

Pool Specs:
approx 20x40 free form gunite pebbletec pool... approx 35k gals(according to some online pool calculators)
1.5hp pump and sand filter
Salt Water Generator
live in Lubbock, TX near farm land
Well Water is my fill source(I assume some of my issues arise from well source)

Leslies Water Analysis
FAC = 1
TAC = 1
Salt = 3100
cyanuric Acid = 50
Total Alkalinity = 490
PH = 7.8
Phosphates = 100
They also told me I have high Nitrates in the pool. They didn't try to sell me anything to lower the Total Alkalinity which seemed strange. My brother was the one who told me I need to add the muratic acid

Until my real test kit arrives later this week I have been using the test strips I have. According to them everthing is pretty much in line other than the high PH reading and high TA readings

My pump runs 24hrs per day as per to the pool builders recommendation
I have since Friday been adding water diluted Muratic Acid at the rate of 128oz every 12 hrs?!?
I also poured in a 128oz bottle of home depot liquid chlorine(today)
Used 3lbs of shock at the direction of Leslies on Sat

Questions
1. Am I adding too much/too litte muratic acid at one time.
2. How much muratic acid can I add at one time and at what intervals
3. I have dark brown almost black spots on the baja bench, steps and a area in the deep end of the pool. It will not scrub off. Is this black algee?
4. Also having issue with scale/calcium build up at water line around pool. Will fixing water issues fix this or do i need some type of addtional chemical to remove.

According to the calculator I am going to need possible 20-22 gal of muratic acid to lower the TA

Sorry for all the newbie question but would like to get my head around maintaning the pool properly

Thanks in advance for all responses
John

 

[frustratedpoolmom]

Welcome John, I would wait for your own test kit to confirm before you purchase 22 gallons of Muratic Acid

In the meantime, while you wait for it to arrive, you need to familiarize yourself with the Pool Calculator. The trick for lowering TA is to lower PH. So....

On the Pool Calculator, enter your "gallons". Then in the "Now" column for the PH, enter your current PH level (this is when you have your test kit). Then in the "target" column, you enter 7.2 for the PH. Now repeat this process for the TA section. Enter the current test result in the "now" box and 100 in the "target" box. Now, go back to the PH section. There will be a "000oz" result in the box next to the drop-down box for Muratic Acid. Be sure to pick out the appropriate strength from the drop-down menu (ie 31%). If you hold your cursor over the "000oz" box, and look up above, it will tell you how many gallons, cups, quarts, etc. that amount equates to. That is how much you add at a given time. Now, this may be a daily addition, a weekly addition, not sure.

You see, aeration, caused by your SWG, will cause the high TA to make your PH drift up. Everytime the PH drifts up to 7.8, you use the acid to lower it back down to 7.2. The repeated acid additions will also lower the TA. Eventually your TA will drop down into the recommended range and the rate of PH rise will decrease or stop. But this rate of drift is different in every pool.

Now, there are instructions in a Pool School article that outlines this process but in a way that you can speed it up and accomplish it in days or weeks time. You need a really good source of aeration for this process to speed it up. Its not required that you do it faster than daily or weekly, provided you are diligent with your PH testing (daily) and make sure you are lowering it when it needs to be. Hope this makes sense.

Your scale is caused by the high PH, TA and CH - but I don't see a CH listed? Depending on how old the scale is and a little diluted acid solution, you may be able to remove it with a little scrubbing/elbow grease. Proper chemistry in the future should prevent it from re-forming.

Don't worry about phosphates or nitrates - as long as you are maintaining the proper FC according to the CYA chart, those things are irrelevant. However, with a FC of 1, that's not enough. Again, use the pool calculator to figure out how much chlorine to add.

Worry about the spots later, when you are feeling more confident and have a handle on things. We can help you sort that out too.

Post back if you need clarification on anything.