New member, first test results, CYA and Ca high

[Taffiedog]

Hi Everyone,

I just found the site a couple of weeks ago and have been reading and learning. I ordered the Taylor K-2006 kit and did my first test with the new kit this evening. I have had the pool for 2 years, but the pool itself is older (not sure how old, but I know the vinyl liner has been replaced once).

My pool water looks crystal clear, but gets a bit of green algae on the walls in the corner every 2 - 3 days. I brush off and clean pool with Dolphin Nautilus cleaner. I now know that even a bit of algae is bad, so I would like to improve the pool water quality.

Currently, I have an inline chlorinator which uses about 10 or 12 pucks per week. I didn't have to turn it up so high last year. I have been 'shocking' with 3 bags of calcium hypochlorite once a week. Since starting to read here, I have been adding bleach to top up chlorine levels, which have been low last couple of weeks (90 degree days).

I run my filter 8 hours a day from 8am to 4pm. I was doing it 11 am to 7pm, but get better chlorine numbers (HTH kit) with the earlier schedule.

Test results from this evening:
FC - 1.5
CC - 0.5
pH - 7.4
TA - 140
CH - 300 with ' floating red bits', 350 with no bits
CYA - over 100. Diluted with filtered water to 50%, measured 80, so total is 160?

I know that I need to drain and replace some water (About 70% according to poolmath), but I am very anxious about doing this and damaging the pool. I think it will be the same if I drain and refill a foot of water four times over, right? (average 5.5 feet deep)

Feedback greatly appreciated.

 

[jaduck]

Welcome to TFP! You are already ahead of most recent converts because you have a proper test kit! Good for you! Bad for algae!

1. Stop with the pucks! That is why your CYA is sky high.
2. Stop with the Calcum Hypo...just adding Calcium that you don't need
3. Partial drain and refill until the CYA is more manageable (30 - 50)
4. Perform a SLAM. Please refer to Pool School!
5. Use only regular old bleach. Add nothing to your pool unless instructed by the experts.

 

[Taffiedog]

Thanks for the advice. I'll get to work!

 

[wrems]

Those pucks are killing you...

You can do multiple partial drain and fills too. It may take some time to get that CYA value down but if you keep working at it you can get it under control. You can't do a proper SLAM until you get this under control so just keep adding plain old bleach for your FC. Remember you still need to pair your FC with your CYA: Pool School - Chlorine / CYA Chart you're not even on the chart... Not sure what the exact daily FC you need to maintain when you're up that high?

Brush and vacuum often to disrupt the algae that's there to prevent it from expanding.

As was mentioned with a vinyl liner you can ignore CH. It's meaningless. Your pH and TA numbers are fine. Just watch the pH for it to climb and when it does give it a shot of muriatic acid to bring it down.

 

[Taffiedog]

Thanks wrems, appreciate your input.
I will keep my FC to between 7 and 12 per the chart until I get the CYA down. I'm being very careful and exchanging water a bit at a time, so it's going to take time.

 

[DaninFLA]

I know that I need to drain and replace some water (About 70% according to poolmath), but I am very anxious about doing this and damaging the pool. I think it will be the same if I drain and refill a foot of water four times over, right? (average 5.5 feet deep)
.

you can definitely do more than 1 foot. check your water table, dig a hole about three feet deep next to your pool. let the hole sit for a few hours. if it ponds up water, that's your water table depth. don't drain pool much below that. if it stays dry, you can empty that far and not be too worried.

but to answer your question, no. four refills will not be the same. 1 foot in a 5.5 avg depth pool is 18%. if you did four 1 foot drain and refills, you would reduce your CYA by 55% (100*0.82*0.82*0.82*0.82)...not 70%.

if would drain 2 feet at least twice. that would be 36% each. two drain/refills - that would be total reduction of 60% and would be a lot quicker for you. but with your CYA levels, you will probably need three, which would be a reduction of 74%.

the CYA test has a pretty big margin of error, especially on the diluted method. do a drain/refill, re-test and then adjust your plan from there. if you do 2 foot drain/refill the first time, probably be more comfortable and maybe do a bit more the second time. take your time and do what you are comfortable with.