Woodlands TX pool needs fixin

[cwuffman]

Howdy folks!

Our pool was installed last summer and I thought it was fine per the pool store. We got all of the numbers where they were supposed to be. Water is crystal clear with an occasional tinge of green here and there but not out of hand.

Then I found this site! I started paying more attention to the fact that each pool test evaluation had cya at 100ppm and listed as OK. My test strips seemed to indicate it was getting higher (tri-chlor tablets). I asked the pool store guy why and he told me that was the highest value they could type into the program. Hmmmm???

Last night I took a normal sample and a 50% diluted sample to be tested. The guy told me the actual test result indicated 130ppm, and the 50/50 diluted sample verified that at about 65ppm.

Here are the numbers from their printout as of last night:

Free chlorine: 3 ppm
Total chlorine: 3 ppm
Combined chlorine: 0 ppm
pH: 7.6
Hardness: 250 ppm
Alkalinity: 100 ppm
CYA: 130 ppm
Total dissolved Solids: 1000 ppm

From what I am reading on this site, partial draining is in order. I am not sure how far to go yet as I have noticed on this site that some folks run the CYA a bit higher in these extremely hot southern conditions. Comments?

By the way, the TF-100 kit was ordered yesterday, and Walmart seems to be the best source of liquid chlorine.

Thanks in advance,

 

[duraleigh]

A partial drain/refill of about 50% should get your CYA manageable. I would suggest testing with the TF-100 as the most accurate reading and then report that.

Meanwhile, in the heat and given that your CYA is pretty darn high, I would suggest a chlorine level around 7-10ppm untill you can start the drain/refill.

 

[cwuffman]

Thanks, Dave.

I've calculated that I need to drain 3.5 ft. to achieve 50% water removal. A couple more questions:

1) Is this safe to do all at once with my plaster inground pool?

2) Will the pool plaster be harmed by drying out or exposure to the sun?

3) I am guessing the pool water will not hurt my grass??? It's been very hot and a shame to waste this much water.

Thanks again.

 

[cwuffman]

Is anybody experienced enough to respond? I have been searching this forum and haven't completely resolved my questions.

Thanks,

 

[Bama Rambler]

1. If the water table isn't a concern then it is.

2. You're draining and refilling immediately after oyu should be fine.

3. A lot of people water their grass with the drained pool water. It'll be fine.

 

[harleysilo]

If you are concerned about your plaster drying out you could tie up a float in the middle of the pool and run a sprinkler to keep the sides of the pool wet while filling with another hose.

I also read about people replacing water as they drain. If your fill water is colder than your pool water you can stick the fill hose in the bottom, and the siphon water off the top with another hose. You would want to start the siphon and measure how long it takes to say fill up a 5 gallon bucket. Then adjust your fill hose to fill at that rate. (I am assuming you have a lower area in which to run the siphon).

I also read about people spreading a big tarp out and weighing it down around the edges of your pool. You start filling water on the tarp and removing water from beneath the tarp. The tarp slowly sinks into the pool as if fills up.

Just throwing that out there.

 

[cwuffman]

Thanks to everyone for the responses. Now to get at it.

 

[calm_like_a_bomb]

I also read about people replacing water as they drain. If your fill water is colder than your pool water you can stick the fill hose in the bottom, and the siphon water off the top with another hose. You would want to start the siphon and measure how long it takes to say fill up a 5 gallon bucket. Then adjust your fill hose to fill at that rate. (I am assuming you have a lower area in which to run the siphon).

I just did about 40% of my pool water this way. Sum Pump on 2nd step fill hose opposite end at the bottom. I did measure the output with a 1 gal bucket just to see how long it was going to take. I eye balled the input side, and then just kept an eye on the water level.

My house is on a VERY small lot. The first time I tried draining my pool using my pool pump on backwash, I flooded my back yard, side yard and part of my neighbors yard with about 3" of water, and the pool only went down about 4". If you don't have alot of space to drain that kind of water you'll likely run into a problem.

I ended up using a sewer clean out to drain my water into. According to the city officals here, they recommend no more than 15 gpm into the sewer system when you are draining your pool. The sub pump i have says it does "upto" 14gpm. My real word gpm thru 100' of 5/8" garden hose was 3gpm (yeah it took a while).

CLB

 

[cwuffman]

Status Update

Rented electric pump from HD. Wanting to drain too much rather than too little, I did overshoot the necessary amount needed to get to acceptable CYA level. After 6 hours the pool looked 2/3 drained. That wasn't too difficult.

After the fill just for grins I took samples to 2 pool stores. CYA numbers reported were around 30 ppm. With the TF-100 kit I can still sort of see the spot after pouring all of the sample mix into the test tube. So I presume I am probably under 20 ppm. This test was repeated before and after hardness and alkalinity adjustments with the same results.

Anyway, after the above adjustments my test kit last night yielded the following:

cl-1.5 (have been adding a lot of bleach the last week due to low CYA)
Ph-7.5 (have been dropping to 7.2 almost daily to lower alkalinity)
TA-130 (see above)
CH-240 (after refill was initially 100)
CYA-20 or less

I have hesitated to increase the stabilizer so far because I will be going out of town for 9 days and wanted to use that opportunity to use up some hockey pucks. According to the pool calculator, I can use 17 trichlor tablets (at 8 0z each) to raise my CYA to a target of 40. Does that sound like an acceptable plan?

By the way, thanks to all for such a helpful source of information.

 

[zea3]

Sounds like a good plan, Carl.

 

[techguy]

I wonder... The range for the most accurate measurement of CYA is 30-100. The store enters 100 for any number over 100. Do they enter 30 for all tests for CYA between 0 & 30? Anything under 30 is honestly pretty hard to judge.

 

[cwuffman]

Yeah, I sort of wondered that too. I plan to go with the TF-100 numbers.

This is also a bit interesting. Pool store "A" (manager type), who I had been "trusting", tested my cya after refill at 30ppm. They told me to first add acid to get alkalinity down and then we would work on other things. A week later after adding only bleach and muriatic acid, a young employee re-tested my cya at 65. I told him I hadn't added ANY cya or trichlor tablets since the previous test. What did he make of that? He sort of shrugged his shoulders and repeated the 65 number. It really is kind of fun going to the pool store.

My wife then out of curiosity took a second sample to pool store "B", (starts with the letter "L"), and they tested cya at 30ppm. Incidentally, this same store had been bold enough to tell me I had 130 ppm before the water drain and that I needed to drain 2/3 of the pool and start over. So they may not all be incompetent. I did notice mountains of buckets of 3" tablets there too.

 

[UnderWaterVanya]

Yeah, I sort of wondered that too. I plan to go with the TF-100 numbers.

This is also a bit interesting. Pool store "A" (manager type), who I had been "trusting", tested my cya after refill at 30ppm. They told me to first add acid to get alkalinity down and then we would work on other things. A week later after adding only bleach and muriatic acid, a young employee re-tested my cya at 65. I told him I hadn't added ANY cya or trichlor tablets since the previous test. What did he make of that? He sort of shrugged his shoulders and repeated the 65 number. It really is kind of fun going to the pool store.

My wife then out of curiosity took a second sample to pool store "B", (starts with the letter "L"), and they tested cya at 30ppm. Incidentally, this same store had been bold enough to tell me I had 130 ppm before the water drain and that I needed to drain 2/3 of the pool and start over. So they may not all be incompetent. I did notice mountains of buckets of 3" tablets there too.

Knowledge is power. You have found out that pool store B at least has one compentent employee and that person understands that high CYA is a problem. There may be hope for them yet.