Before/after 50% refill, still out of balance

[tlbig10]

New pool owner here as of last year. I decided to start the TFCP method this season after messing with 4-in-1 chlorine tabs and Shock last year (so far just adding Clorox Bleach from Costco for chlorine) and here are my before/after results using the TF-100 test kit when I replaced 50% of my water:

Before:
2014-05-15
Chlorine: 0
Free Chlorine:
Combined Chloramines:
Total Chlorine (FC+CC):
pH: 8.2
Calcium Hardness: 700 ppm
Total Alkalinity: 180
CYA: 100

2014-05-19 drained 50% of pool and refilled

After:
2014-05-27
Chlorine: 3 (just added 121oz Chlorine an hour before testing)
Free Chlorine: 4 ppm
Combined Chloramines: 0
Total Chlorine (FC+CC): 4
pH: 8.2
Calcium Hardness: 625 ppm
Total Alkalinity: 170
CYA: 70

So my pH, CH, TA, and CYA came closer in line, but are still out of whack. My main concern is having my chlorine levels burn off in three to four days which leads to the beginning stages of algae forming on one end of the pool wall.

With AZ water being so hard, how can I get my CH, TA, and CYA lower? The Pool Calculator still tells me I should replace 58% of my water to come in line with CH and replace 43% to lower CYA. I know I need to lower CYA and pH to allow the chlorine to last longer, but I'm not too keen on replacing 50% of the water for the second time in a single month. Thanks for your guidance.

 

[DHoover85]

First off you mention AZ water being so hard, can you quantify that? run the FC, CC, PH, CH, and TA tests on your fill water? post those results and I'm sure someone around here can help you with your balance. your PH and TA can be lowered using Muriatic Acid, and pool Calculator / pool math will tell you how much. CH you will only be able to lower to the value you get from your fill water, unless you start harvesting rainwater (CH=0) and I don't know how rare that may be in Mesa.

 

[UN1017]

With AZ water being so hard, how can I get my CH, TA, and CYA lower? The Pool Calculator still tells me I should replace 58% of my water to come in line with CH and replace 43% to lower CYA. I know I need to lower CYA and pH to allow the chlorine to last longer, but I'm not too keen on replacing 50% of the water for the second time in a single month. Thanks for your guidance.

So my pH, CH, TA, and CYA came closer in line, but are still out of whack. My main concern is having my chlorine levels burn off in three to four days which leads to the beginning stages of algae forming on one end of the pool wall.

Welcome to TFP.

You have already taken many of the steps needed to adjust the levels which you are concerned about. You brought your CYA down to 70, which is a little high, but in AZ it might be ok.

Unfortunately, as Dhoover85 was touching on, your fill water CH (and TA too) is likely above recommended levels. Short of you trucking in water with a lower CH, you will need to manage it the best you can.

That takes us to the last point, your TA is high but you will need to follow these steps by reducing pH and aerating, in order to lower it.

So my pH, CH, TA, and CYA came closer in line, but are still out of whack. My main concern is having my chlorine levels burn off in three to four days which leads to the beginning stages of algae forming on one end of the pool wall.

Chlorine levels are not meant to last three to four days. You need to dose daily (maybe every other day if you're lucky). Extreme sun exposure makes it very challenging.

You need to focus on your FC and CYA. Keeping an effective level of FC will keep that algae in check. Monitor/adjust your pH daily and your TA should fall in line on its own.

 

[BoDarville]

The reason that the CYA did not drop as much as you were expecting is that the actual CYA level was very likely higher than your initial reading of "100". This is because the maximum reading on the CYA view tube is 100. Whenever a CYA results comes back at 90 or more, we recommend retesting using the procedure described in post # 8 on this page: Extended Test Kit Directions.
Since your current CYA is at 70, you do not need to worry about this now...just posting for future reference and for the benefit of others reading this thread.

Likewise, the CH did not drop at a rate corresponding to the % of water that was replaced due to the hardness of AZ water. I have read that there are reverse-osmosis treatments that can reduce CH and that this service is most popular in AZ and SoCal relative to other parts of the country.

 

[duraleigh]

Welcome to the forum.

The Pool Calculator still tells me I should replace 58% of my water to come in line with CH and replace 43% to lower CYA. I know I need to lower CYA and pH to allow the chlorine to last longer, but I'm not too keen on replacing 50% of the water for the second time in a single month.

You have numbers you can live with but they are marginal. Leave your numbers right where they are if that's what you want.

The important thing to understand about TFP is learning how to deal with what you do. If you choose to keep your CH high (and it will go higher) then learn what you do to compensate for that. If you choose to keep your CYA @ 70 ppm, learn what steps you take to keep normal levels.

You are not far out of "normal ranges but the kit and pool math is telling you you are borderline and need to compensate for it.

 

[frustratedpoolmom]

In preparation for a possible future repeat drain/refill, I agree with the suggestion of testing the fill water and posting the results.

If you don't want to do it right now, get your PH down to 7.2 ASAP to avoid the high CH/PH/TA from causing scale. Use PoolMath and muratic acid.

I've run with a CYA of 70, and it's doable if you diligently test your FC and PH daily and keep those 2 in range - you can manage for awhile if another drain/refill is not your preference right now.

 

[timerguy]

Then again, you'll be using more bleach for the higher required FC. Do a cost benefit analysis.

 

[YippeeSkippy]

I don't understand these test results:

Chlorine: 3 (just added 121oz Chlorine an hour before testing)
Free Chlorine: 4 ppm
Combined Chloramines: 0
Total Chlorine (FC+CC): 4

How can you have 3 Free Chlorine, zero Combined Chloramines yet the Total Chlorine is 4? The math doesn't add up... this isn't some strange Common Core math problem is it? LOL

 

[UN1017]

I don't understand these test results:

Chlorine: 3 (just added 121oz Chlorine an hour before testing)
Free Chlorine: 4 ppm
Combined Chloramines: 0
Total Chlorine (FC+CC): 4

How can you have 3 Free Chlorine, zero Combined Chloramines yet the Total Chlorine is 4? The math doesn't add up... this isn't some strange Common Core math problem is it? LOL

I think tlbig10 was reporting results from the OTO, which look about 3. Then did the FAS-DPD with an FC of 4 and a CC of 0.

 

[roppy]

I live in Mesa as well and did a 3\4 drain a few months ago my CYA was off the chart. Once I refilled my CH was close to 550 and TA 200. All I did was lower my PH to 7.2 and maintain that level for the past 2 months now my CH 350 and TA 130. Just keep you PH down and you will be fine. Every time I add water of course my numbers go up a little. As for chlorine my pool is in direct sun all day so I find as it gets hotter I am adding 32 oz a day of 10% chlorine with a Cya of 40.

Sent from my LG-LS970 using Tapatalk

 

[tlbig10]

Thanks for all the support. I will keep this updated with my adventures in pool maintenance. I'll do an analysis on regular water and post my results in here for anyone else in AZ wanting to have an idea of what kind of water we have in the Phoenix area.

roppy - thanks for letting me know how much chlorine you're adding on a daily basis. I thought what I was adding every three days (120 oz) was excessive, but I'm not too far off. I need to get on the daily check routine and stay on top of it.