Help with balancing water

[swinaz]

We had an algae problem a week ago. took a water sample to the local pool store on 6/6 after adding 2 gals of liquid chlorine:
FC 2; TA 2; CYA 150; TA 120 pH 7.5 phosphates 2000; dissolved solids 3000

Added 6# of shock over 36 hours. Chlorine not holding. but Algae getting under control with some added brushing.
Drained a foot of water and added back hose water 3 x over 3 nights.
Today's water sample results:
FC .5; TA .5; CH 220; CYA 30; pH 7.4; Phosphates 2500; dissolved solids 1900

backwashed filter today and ready to add m. acid, wait til sundown and add shock. Pool store recommend Phos Free, but after visiting your site I see it's a money maker for the store.
Any other recommendations?
Location: Phx Arizona, 19,000 gals, IG Plaster blt-1999 pump 1.5 hp Nautilus FNS 48 DE filter

 

[RobbieH]

What "Shock" are you adding? Your CYA is already at 150, and adding "shock" is more than likely just increasing your CYA level.

My recommendation is for you to read Pool School, specifically How to Shock. pool-school/shocking_your_pool

You are going to need a QUALITY test kit, such as the TF-100 from tftestkits.net to do this. AND, you are almost certainly going to have to drain a very large amount of water and refill. Your CYA needs to be down around 40-50, not at 150+. Shocking at a CYA level that high is going to be a real pain.

Ignore the phosphates.

 

[linen]

Welcome to tfp, swinaz

RobbieH has some great recommendations! Here are mine:

Pool store recommend Phos Free, but after visiting your site I see it's a money maker for the store.
Any other recommendations?

Take a look at this poolschool article, it details the tfp recommendation on clearing a pool: http://www.troublefreepool.com/pool-school/defeating_algae There are a couple of links in there that are very important to read.

Also, to be most effective you will need to have an appropriate test kit. The fact that the two results for cya you have are so far off, suggest the pool store results you have are not reliable. See this link for details: http://www.troublefreepool.com/pool-school/pool_test_kit_comparison

Let us know if you have any questions!

 

[swinaz]

I am going to shock the pool according to your directions and do an OCLT with a Taylor k-2005. Will let you know how that goes.

 

[jblizzle]

Was it a typo that the first test shows CYA of 150ppm and the second one shows CYA of 30ppm. If those are the numbers they gave you, then that just proves how bad pool stores are at reporting CYA as you would have had to replace 80% of your water to get that drop.

Summary: Get your own good test kit.

EDIT: The K-2005 does not have the FAS-DPD chlorine test that is required to accurately test your FC and CC. Luckily you can buy just the FAS-DPD test and add it to your K-2005 to have the equivalent of the K-2006 which we recommend.

 

[swinaz]

good to know about the test kit add-on.

No that wasn't a typo and we DID drain water from the pool for 3 nights in a row, removing and replace about a foot or more of water each time.

 

[jblizzle]

Three 1 foot drains would only lower your CYA level by 80% if your average depth was 2.5 feet.

Bottom line pool store was off on at least one of those tests. The bad part is you don't know which ... so hard to know what FC level to target.

Have you tested it for yourself yet?

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone

 

[lightingguy]

Those test results are nonsense.

You lost 30% of your TDS, 80% of your CYA and actually gained 25% of your Phosphates - it's just not credible

The only problem you are having with the chlorine is that you aren't adding enough of it. What you add is instantly used up by the algae in the pool. It's doing it's job - you are seeing improvement in the algae - but it's just not enough.

It's sounds like you are on the right track. A good test kit (with an FAS-DPD chlorine test - not just the drop kind) will really set you free from the round and round at the pool store.

 

[swinaz]

thanks to all who posted. I added chlorine/bleach tonight. Will get recommended tester asap and kiss the pool store goodbye. I agree, and feel like I'm on the right track; just need to get enough FC.