Insight to these just taken test results

[tstex]

Hello to all,

Let the pool guy go in Dec and have been doing things myself...I have been using 8% bleach and 32% M-Acid to keep the pool in spec.

Well, I just did a set of tests w the TF-100 Test Kit & Stir-stick, here are my results:

FC = 2.5
CC = 0, so TC= 2.5
CH = 437.5*
TA = 40*
CYA = 40
pH=7.2-7.3
water temp 68-70
16K gal in-grd
water visual - crystal clear and no issues w algae or pebble-sheen spotting w either light or a bit darker splotches - pretty uniform

* tested each of these twice

pool was filled w water in jan/feb 2015 for first time

I had an issue w the pebble-sheen discoloring last summer, so the gunite company did a no-drain acid wash for 8-9days...it fixed the problem. He told me to keep the pH is the lower range of 7.2 -7.5 so that's what I've been doing...I think this is why the TA is low, yes?

Since the pool guy was using pucks and I only liq CL, my CYA has dropped from 60-65-70 to 40. I've only used liquid bleach for last 4-5 mo's..I made the pool guy take out the pucks the last mo he was here and use liquid CL

I believe the TA is low bc the acid levels have been kept lower...I'm going to ask the gunite guy can I now keep the pH a little higher to 7.5

I have noticed that the consumption rate of the CL is going much faster, prob due to lower CYA value, water warming and decent runs of a lot of sun-light. In the winter, we had a lot of cloudy days and rain...I did not swim in the pool during winter, but did use the spa here and there and it empties into the pool

So, what do I do to get the CH down to 250-300? I let rain water fill the pool many times in late fall and winter, and my only other option is the city water. I'm sure it's mineral rich. I might want to get the gunite guy out and see if he thinks the plaster/pebble-sheen is done leaching CH from being a new pool.

I would appreciate your pool chem experience on what I need to do? Thank you very much, tstex

 

[jblizzle]

First, something is off with your CH calculation. It should be a multiple of 25ppm or 10ppm.

Every time you add acid, you lower the pH and the TA.
Without a SWG, I would suggest raising the TA up to around 70ppm.

CYA should not really drop very much unless you are replacing water ... maybe up to a 5ppm loss per month is normal.
And yes, with the lower CYA level, you will see a higher FC loss due to the sun.

Only way to lower the CH is to replace the water with water that has a lower CH. Have you tested your fill water? Harvest rain is a good idea

 

[Richard320]

I see a math error somewhere. The Ch test uses a multiplier of 10 or 25, so 437.5 doesn't seem possible. How big was the sample and what factor did you use when you multiplied drops? Even if 437.5 were correct, it's not unmanageable at all. In over five years, my pool CH has never been that low.

The low TA is probably due to constant acid additions and rain dilution. Rain has no TA in it.

Your deductions about the FC consumption are exactly what I would have suggested.

Redo that CH test and decide if you want to replace any water or not, and if so, do that before you start dumping chemicals in the water. Then it's just a matter of adding some CYA granules and some baking soda. Pool School - Recommended Pool Chemicals will tell you the preferred way of adding each.

 

[tstex]

Thanks Jason/Rich,

First, I did the CH twice...one time 18, one time 17, so I took the avg, thus 17.5 x 25 = 437.5...sorry for the confusion.

Next, we had some 5-6" rains, and in some instances more where water was flowing out the drain...I decided to turn-on the pump during big rains so I would circulate the rain water and not lose it all of the top, thus better dilution of CYA and CH, and TA, combined w a lower pH.

As far as CYA, I could go w a temp puck alternative to get a liq CL break and add 2ppm per puck till it raises the CYA to 55ish range. I'll check the pool-school math calculator to determine the Na I will need to add to increase the TA.

Finally, re the CH, good idea on checking the CH of the city water. what is your thoughts on the new plaster leaching out the Ca, and that process should be coming to an end, yes? I'd be stretched to trap rain water w all our gutters, downspouts into the drains and to the street...we had a 9-11" rain last June and it was the drainage system that saved an overflow of landscaping darkened water that went down the drain and not into the pool.

Finally, if my fill water has a 400+ CH reading, how else can I treat the water to effectively lower the CH w out a detriment to the pool/pool system?

Again, thank you very much, I appreciate your feedback.

 

[pooldv]

I doubt if your CH will be 400, I haven't seen tap water that high anywhere. Many people on TFP manage CH much higher than 400, many 800+, some 1000+ and a couple over 1200. Keeping your CSI in check, preferable slightly negative, -0.1 to -0.2 will prevent plaster issues or scaling.

 

[tstex]

thanks DV - I'll test the tap and post back later today the results...

we have a spillover spa into the pool...when the water dries on the spillover now, it is almost all "chalk white". since all our pool [and decking' stones are travertine, we cannot apply the easy fix of acids, that bubbles Ca and other similar minerals. It's either sand-blasting or wet-sanding w 350 grit paper. I already had to drain the spa 3-4" past the trav-tile line, aggressively sand them all down [9ftx9ft 18" raised spa], then I sealed them twice w a high end sealer/enhancer. I used a sponge so the applic was quite thick. I know I'm going to have to do the same w the spillover and the entire pool trav-tile line of 100 ft. There is also a 2ft back wall w 4 raised columns [2'x2' and 20" tall] of 2 scuppers and 2 firebowls and all topped too w travertine, stones throughout...we have 1300sqft of travertine decking so I'm thinking of buying all the proper p-tools and accessories and getting into the backyard travertine stone restoration business, but, and w a zero profit basis. but a 100% self and visual satisfaction My golden retriever also appreciates a quality look....wife too, daughters, that's another ch.

So, a lower CH is definitely in the plan..I really empathize w the pool folks w those extreme CH ratings. I'm not the only one in the n-hood w Ca deposits on all of their water lines and other...I'm all ears if anyone has a viable and cost-effective solution.

As always, thanks a million for the input - tstex

 

[pooldv]

It isn't the amount of CH in the water that is causing the issue it is the CSI. I had the same issue a year or two ago with a CH line building up on the waterline tile. This was because my CSI was too high. Dropping it down to -0.1 to -0.2 made the line go away and stay away ever since. That will not harm any stone it just keeps the calcium in solution in the pool.

 

[tstex]

10-4...thanks DV...I'll check out the CSI and see what I can do to lower so I'll suspend the CA rather than precipitate it..tstex

 

[Richard320]

Okay, so we'll call the CH 450.

Plugging your numbers into poolmath, we get a CSI of -.68, which will start leaching the plaster and grout holding things together. Not good -- way too high.

Leaving everything alone except raising CYA to 50 and TA to 80 will put CSI at -.33 which is still low enough to keep Calcium in suspension yet not damage the plaster. When the water warms up to a comfy 80, CSI would get to -.24. And knowing pH will rise with people splashing and spillover from the spa, even at 7.8 CSI will only be to +.34. So as the water warms you keep pH down below 7.6 and don't adjust TA above 70 and it's all fine.

The ring around the tub is caused by evaporation, and there isn't a whole lot you can do about that.

Play around with poolmath. Plug your numbers in and start manipulating the target and see what each parameter does to the CSI. You'll soon discover that CH itself affects the CSI very little. It's pH, TA, and temperature that can really bounce that number around. Try to keep it close to zero but tending towards negative and your CH won't be a problem.

 

[tstex]

"Plugging your numbers into poolmath, we get a CSI of -.68, which will start leaching the plaster and grout holding things together. Not good -- way too high."

Thank you very much Rich. But isn't -.68 "too low", bc if I move to -.33, which is making the CSI higher, correct?

...-1.0 to -.5 to 0 to .5 to 1.0...the increase is from left to right, correct?

I'm remote from pool math calculator but what Na based product should I buy/make/model and an est of how much should I add when I get home? Once I get this stabilized, I'll get the app for pool math calculator and start running the numbers and document my path...pls let me know and if I have the CSI right or not? Thank you RIchard

 

[Richard320]

"Plugging your numbers into poolmath, we get a CSI of -.68, which will start leaching the plaster and grout holding things together. Not good -- way too high." Thank you very much Rich. But isn't -.68 "too low", bc if I move to -.33, which is making the CSI higher, correct?

...-1.0 to -.5 to 0 to .5 to 1.0...the increase is from left to right, correct?

Think absolute values. That's how I think of it, but you are correct, it is too low.

I'm remote from pool math calculator but what Na based product should I buy/make/model and an est of how much should I add when I get home? Once I get this stabilized, I'll get the app for pool math calculator and start running the numbers and document my path...pls let me know and if I have the CSI right or not? Thank you RIchard

To raise TA you add Sodium Bicarbonate -- Baking Soda. Poolmath says about 9½ lbs. But if you find four pound boxes, just add two. Close enough. 8 lbs will raise TA by 36 and raise pH by .07, barely noticeable on the color block. 9 lbs will be 40/.08. Brand doesn't matter. Just stop at a grocery store or a big box store and grab some on the way home.

 

[tstex]

Perfect...thank you very much Dave...if you ever make it to Houston, lunch on me....

BTW, w all the grade school and jr hi school math homework I've had to review, X-axis number line of - and + values has been drilled into the brain :joker: My daughters would be on my buxx if I said otherwise

I'll get 2 4lb's, toss in and test in 30 mins...I crank the pump and distribute near pool jets...thanks again

 

[tstex]

****UPDATE****

I performed a control test of the tap water for CH...5 drops so CH = 125...man, what a stacked deck...In or around West Houston for City water, what is everyone's CH? Thanks if you reply.

Next, I added 8lbs of NaHCO3, I bought 12lbs. New TA = 70

pH went from 7.2 to 7.5 maybe 7.6 it's a micron size darker than the 7.5 color...I might add 1lb more to see if I can get TA to 80..I'll do that tomorrow am. The TF-100 Kit said the ideal range was 100-120 for CL based pool...thoughts?

FC = 4 now from eye-ball test, maybe 4.3

I'll let all of this stabilize over night and ck TA & ph again Sat am

Again, what a great board...Appreciate everyone's help - tstex

 

[pooldv]

Nice work so far! We are revising our thinking a little on TA relative to PH. It is OK to have TA lower as long as your PH remains stable. Let it sit at 70-80 for a couple or several weeks to see if your PH remains stable. If your PH stays stable and your CSI is good then we're all happy.

 

[tstex]

Ok, thanks dv...What are your thoughts on a 70 TA vs 75-80?

You use city/municipal water up in DFW? What is your CH?

Re pH, I have a call into the gunite comp to see what he thinks about a higher pH now [7.2-7.3 to 7.5-7.6], if plaster is now stabilized.

Thanks again, tstex

 

[tstex]

quote from pooldv:

"Nice work so far! We are revising our thinking a little on TA relative to PH. It is OK to have TA lower as long as your PH remains stable. Let it sit at 70-80 for a couple or several weeks to see if your PH remains stable. If your PH stays stable and your CSI is good then we're all happy."

question: When you say "as long as your pH remains stable". can you pls elaborate on what this means relative to my pool chemistries? I just checked my pH and it was prob 7.7-7.8 My FC was 1 to maybe 1.5 these were both done w the quick pH & CL test. I added CL & M-acid and now FC = 5+ and pH = is btw the 7.5 - 7.2 shades.

Do I need to perform any of the TA's, CH or CYA tests. or more detailed CL tests?

Thank you very much, tstex

 

[JVTrain]

TA is a very flexible number, one that has a suggested range but will be different for everyone's pool. TA determines the ability of your pool to buffer pH changes. You need some to make sure your pH doesn't fluctuate too much in response to acid or base additions to your pool. Too much TA however will lead to fast pH rise. This is because at higher TA levels, carbon dioxide outgasses from your pool quicker with aeration, making your pH rise faster. Aeration happens all the time in a pool and is increased by swimming and water features.

The guideline goes like this. Maintain your pH by keeping it between 7.2 and 7.8. 7.5-7.8 is ideal. ONLY lower your pH when it goes ABOVE 7.8. Lower it to only 7.5 unless you're actively trying to reduce TA from a high number (>100) that's causing fast pH rise. Eventually you will have to wait longer and longer times before your pH rises above 7.8. When this happens, your pool has reached it optimum TA level. That may be 90 ppm. It may be 70 ppm. It may be 60 ppm. Basically, just maintain your pH with a light hand and the TA will take care of itself.

 

[tstex]

Thanks JV, I appreciate the explanation and understand.

We have huge spa w a spill-over into pool w a short waterfall of 4-6". Therefore, as long as the pump is running, its getting aeration. we also have 2 scuppers, but they are usually run just long enough to circulate the water chemistries...As noted previously, I was keeping the pH lower per the gunite comp's request...the 1 year mark has just passed so the 7.5-7.8 shall now the norm...thanks again, tstex

 

[tstex]

I added a little m-acid to the pool early yesterday morning to the 7.5 range after a measurement 30 min's later...ran the spa last night and took a measurement this morning and still at 7.5 pH...I'll keep the board posted -appreciate the feedback - tstex