New pool owner - just getting started

[Undertow]

Hello everyone,

Last week we purchased a home with an inground pool and now that we are settled a bit I'm ready to get started on my pool maintenance. I bought the Leslie's Total DPD Test kit and did a test last week. The CYA was measuring off the chart but everything else was within range. I took a sample up to Leslie's and had it tested to double check my numbers and the kid said everything was good to go and within range (said the CYA was at 60). Since we were moving I have not had much of a chance to mess with it again until today; the water is clear and the pool looks good. I did another test and got the following numbers:

FC - 0
TC - .5
pH - 7.8
TA - 120
CH - 310
CYA - 100+

Since I'm new at this and don't totally trust my testing abilities yet, I then decided to take another sample to TexSun and they tested it with their machine and got the following numbers:

FC - 0
TC - .5
pH - 7.9
TA - 108
Adj. TA - 63
CH - 274
CYA - 151 (she said it was as high as their machine would go)

TexSun was who the previous owners had used to maintain the pool so I asked about the high CYA and the affect on chlorine; she said "some manufacturers will tell you that." It looks like they have a more accurate testing method, but my faith in their information is quickly diminishing. To get back in range, she suggested 12 pounds of BioGuard Balance Pack 100, 2.5 pts of muriatic acid (split over the course of two hours), and 2 bags of "multi magic" shock.

I went ahead and bought the muriatic acid and got 2 182oz jugs of Clorox regular bleach on the way home.

I added 1 jug of the bleach about 30 minutes ago just to get some chlorine in there. The pool calculator show that I should put in 18oz of muriatic rather than the 2.5 pints the pool store recommended. I know with the CYA that high it will require a significant water change to get it down, can this be achieved over time with backwashing if I use bleach? We are also not getting much rain and its been plenty hot, so I suspect I'll be adding water frequently. Also, I'm not real clear on the TA and Adj. TA - should I add some type of Alkalinity up?

Any recommendations are greatly appreciated.

Thanks!
Jake

 

[zea3]

Hi Jake, welcome to TFP! You can run the CYA test mixing 1 part pool water with 1 part tap water, then adding equal parts of that mixture and CYA reagent and reading it in the view tube. Multiply the result by 2. It won't be an exact reading but it will tell you if you are looking at CYA of 200 vs 100.

The only way to lower the CYA is to drain and replace a percentage of the pool water. You may have to do a series of drain/replace cycles to get the CYA to a manageable level of around 60 ppm. The test only measures up to 100 so it could be well over 100, 200 or 300. CYA does not evaporate out of the water, so topping off will not help, and relying on backwashing alone will not replace enough water. If you decide to drain and refill, that should be done first then take the pool through the shock process ( if needed) and balance the water.

Currently your TA is just fine and I would leave it alone. We generally don't mess with adjusted alkalinity. You need to get some chlorine in the water and bring down the pH a little if you decide not to drain at this time. I don't know if your area is on water restrictions, but you can use the pool water to water the lawn if you drain. With your current test results, your FC range is 11-18 and the shock level is 33. To bring the FC from 0 to 18 would take 3 gallons, 3 quarts of bleach. If you allow the FC to drop below 11 you risk algae bloom.

 

[anonapersona]

Do test the TA of your tap water. Some areas have high TA that means as you drain and fill the pool, your pH will rise more than normal due to high TA. Not a big deal, that can be adjusted fast or slow, but if your TA is above 300 like mine is, you need to be aware of that.

 

[Undertow]

@zea3 - Thanks for the information. I'll go ahead and get some more bleach in there for now until I can start the water change process.

@anonapersona - I'll test the tap, would be interesting to see whats going in. I'm not too far from you, I grew up in the Woodlands - my wife and I just recently moved to Kingwood.

I've also got some air bubbles coming out of the jets, I suspect it is coming from a small leak at the filter head.. but I'll start another thread about that.

 

[Richard320]

The big question: What does the pool water look like right now?

If the water is clear, you can maintain it with super high CYA; I did it all last year due to water restrictions. You'll have to maintain FC real high (You don't actually use any more day-t-day, it just has to stay at a higher level) so you'll never be able to use the color-matching chlorine test, have to use FAS-DPD every time.

The downside is, what if you do develop algae? Then you pretty much have to drain, because otherwise you'll be buying chlorine by the barrel, not the jug, to get it up to shock level.

So... if the pool is clear, and you have more pressing concerns in your life, stay on top of the minimum FC, and do partail drains & backflushes to slowly bring CYA down. If water is plentiful and you have a weekend to spare, drain, refill, and rebalance.

 

[Undertow]

Hi Richard,

Thanks for the reply. The pool water looks great right now. I'm assuming by the high level of CYA that it has been maintained as is for quite some time. I added more bleach so I'll test the water again tomorrow and see what it looks like.