Algae starting to form on pool walls,

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smksignals

smksignals

0
Oct 4, 2017
15
Gilbert, AZ
Pool Size
30000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi everyone,

This is my second post here. I did an intro just over a year ago and kind of faded off for awhile, continuing down the path of the dark side (pool store). Well I am all in now. I did a drain and fill about a year ago with the help of a pool service and this year I have a slight algae problem. It is starting to collect on the walls. I have been doing the 'standard' shocking and brushing so far this season. I have only used 3"tabs and un-stabilized shock as sanitizer over the past 5 years.

I bought the TF100 and these are my readings as of last night-

FC 4.5 (9 drops)
CC 00 (I did the 5 drops of R0003 and the solution looked pretty clear. May be a slight haze of pink. One drop of R-0871 and it was definitely clear)
PH between 7.5 and 7.8 - really hard to tell with the test block.
TA 120
CH 500 (at drops 18-20 the solution was a bit purple? Stopped there. Maybe should of kept dropping until blue?)
CYA 100+ below the 100 line on the cylinder. The pool store had 129 on their report this past weekend.

I have a pool water recycle service coming in a week. I really don't want to drain and fill again in this heat. (30,000 gallons). I have read good things about this service. Once the water is recycled and the CYA is lower I will come back to this thread with more balanced readings and ask for advice on if I need to SLAM.

Any advice or suggestions regarding the notes above is welcome.

Thanks, Kurt.
 
Last edited:
Welcome back!

We're here to help when you need it. We've seen some good results from the RO service. Can you give us a round figure price? It will help others decide on how to deal with drain vs. RO decisions in the future.

You probably know the horrors of solid forms of chlorine, so I won't dwell on it. Nonstabilized shock is likely cal-hypo which drives up CH levels.

Given chlorine prices, there's been a strong trend towards SWG installation. Something you should consider unless you have the time to dump liquid chlorine in the pool daily. You would need a unit rated a twice the pool volume, so that limits your choices to 60K gallon units. The RJ-60 would be a good choice, assuming you don't have Pentair automation.

For the CH test, keep going until there is no further color change, but don't count the last (no color change) drop. With high CH fill water, I would guess your CH is higher than 500. Does your home have a water softener? If so, find a way to top off the pool with softened water to keep CH levels stable.

Report back and let us know how things worked out.
 
I would also recommend doing a diluted CYA test. Mix 50/50 pool water and tap water, then use that mixture to do the CYA test. Multiply result by 2. Let us know what that comes out to be. :)
 
Sorry about the late response, I promise I am not ignoring you all...:rolleyes: I got hit with a pretty nasty cold. This morning was the first time I was able to test again and post here.

Regarding the RO treatment it is scheduled for next weekend. I will report back the details once complete.

The only change since my last #'s is that my bobbers were low on tabs. I refilled both. I run 2 bobbers with 3 tabs each. 6 total. I know, but that's what the pool store told me to run.:(

Here are today's #'s -
FC - 3
CC - 0
CH - 350 The 14th drop was the first color change to a slight purple
TA - 130
PH - again between 7.5 and 7.8, it's really hard to tell exactly
CYA - Quite a bit below the 100 line. I did IceShadows suggestion and did a second test with 50/50 tap water and pool water. That test was just above the 100 line. (So close to 200 true CYA)

There is a bit of algae building up again on the walls. I am going to buy some liquid chlorine for temperary help and brush the heck out of the pool again. I am hoping for good things with the RO treatment next week so I can start all over with the TFP teachings !!

Thx, Kurt.
 
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Hello,

I had my RO service done this weekend and am very happy with the results. The before and after logs are available in my profile pool math link. The CYA was brought down to zero. The TDS came down from 2200 to 450. I am waiting a few days to adjust the calcium hardness and stabilizer. The water is super hard here. I also don’t want to over stabilize in case there’s some residue on the walls that leaches out. Once the water is balanced I am going to do an OCLT to check for algae.

There was a question on cost. I am in the Phoenix metro area. My service provider charged .03 cents a gallon. My size pool took 24 hrs.

If anybody wants to chime in on my pool math numbers I would appreciate it. I’m brand new to the trouble free method. I’m trying my best to absorb it all.

Thanks Kurt.
 
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Hey Kurt,

Glad you got the RO done. The price seems reasonable compared to costs in my area.

How do you plan to chlorinate as you move forward? I'm guessing no solid forms of chlorine, right? Liquid chlorine will need to be added daily during swim season. A SWG is a great alternative.

Do you have a water softener for the home? With high calcium fill water, CH levels will continue to rise with evaporative top offs. If you can hook your fill line into softened water, you may never have to do RO again.

Enable CSI tracking in Pool Math. Try to maintain CSI in the 0.0 to -0.30 range. That will be a challenge until you bump up CH a bit. Add enough calcium chloride to increase CH 200. I see you added cal-hypo which is fine for now. But discontinue use when you reach CH target.

For now, get 4 ppm of chlorine in the pool. Use the sock method to add 30 ppm of CYA (sold as chlorine stabilizer). You can bump that up to to 40-60 to protect FC from the AZ sun, but starting at 30 will ensure you don't overshoot your target. Here's an excerpt from Pool School describing the sock method:
  • Solid/granular CYA should be placed in a sock and the sock put in the skimmer basket or suspended in front of a pool return. If suspending near a return jet, ensure the sock cannot rest against the pool surface since the granules are acidic and could potentially discolor the surface. After adding CYA you should leave the pump running for 24 hours and not backwash/clean the filter for a week. After soaking for about 30 minutes, squeezing the sock periodically will help it to dissolve faster. Test and dose chemicals in your pool assuming the amount of CYA added is in the pool according to Poolmath. CYA can be tested the day after it is fully dissolved from the sock.
Leave pH and TA alone for now. When pH gets to 8.0, add muriatic acid to drop it 7.6. With low CH levels, you don't want to lower CSI to an over-aggressive range.

Not sure on how the water looks, but once you get things stable, complete an Overnight Chlorine Loss Test to determine if you need to SLAM Process.
 
Done with pucks !! I am using liquid chlorine going forward. I will probably look into getting a SWG in the near future.

I do have a water softener for the house. I will check into connecting it to my pool fill line. Sounds like a good idea.

I'm going to add more chlorine tonight. I will be adding CYA soon. I am definitely going a little bit at a time. I do not want to overshoot my target.

I turned on CSI tracking in PoolMath. I do need to get a thermometer for the water. I'll have that entered soon.

Regarding the water, it looks great right now. Really happy with the RO service !!
 
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smksignals said:
I do have a water softener for the house. I will check into connecting it to my pool fill line.
Click to expand...
This is great! If not, plan on another RO service next year. Calcium is your nemesis.

With a SWG, if you plan to be in the house a few years, it will pay for itself. With the convenience factor, it will pay off for itself in month.
 
So it’s been a week+ since I did my RO service. I want to start raising my CH and CYA. Pool math logs are in my profile. I’m going to start raising both in small increments. Is there a sequence to raising, or do one before the other? Thanks as always, Kurt.
 

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Well the results are in! CYA is at 30. I can still see the dot at 40. Filled the tube to 30. Did a quick glance waist high and sun at my back. Did not see the dot. If I stare down the tube with one eye closed I have to try real hard to see it.

OCLT-
Sundown. FC 3.5 CC 0
Prior to sunrise FC 3.5 CC 0

Woohoo!!! I really wish I dove into this site when I first registered in 2017. I then thought a little more serious about TFP when I did an intro a year ago. 1 year later and finally, I am all in! Took way to long. Thank you everyone!!!
 

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