New Member - 1st Test Results

[tchap07]

I've been reading this site since we purchased our house and have never taken care of a pool before. Moved in about 2 weeks ago and the test kit finally came in last night. Pool is clear.

FC: 6.5
CC: .5
PH: 7.6
TA: 100
CH: 230
CYA: 150

I think I did the CYA test correctly. First time I did it was over 100. So I filled the tube with pool water up to the 7 ml mark, tap water to 14 ml, shook it then emptied down to 7 ml mark. Added the reagent to 14 ml and performed the black dot test. Filled it to 75 ml x2 makes it 150. Is this correct?

Do I need to tackle the CYA first or FC? Previous owner said he had to fill the pool a couple of inches every other week during the heat of the summer. Over time would this lower the CYA? I don't want to drain my pool 60% to get the CYA down but if I have to then I guess it is my only choice. Also, Pool Math said I need to get FC to minimum of 11 given my CYA or 109 oz. of bleach. A little less than a gallon of bleach is fine but don't want to have to add that every week. I guess ultimately what I am asking is can I wait for the CYA to come down over time or will I be dumping gallons of bleach in the pool every week and should just go ahead and drain?

Thanks for the help. Love the site.

 

[JVTrain]

I would recommend lowering the CYA. Evaporation will not remove CYA. Only the water evaporates, not the CYA. Draining is the only way to lower CYA, outside of having a reverse osmosis treatment on the pool ($$$$$). Maintaining a pool with 150 CYA is possible but not practical. You will have to go through more bleach than you'd like if you leave the CYA alone and maintain adequate FC levels. However, FC is a consumable. It must be continually replenished. Even at a CYA of 60 ppm, you'll likely need to be using a gallon of bleach every other day in the summer time for your size pool, give or take a bit. If you're not up for that, you sound like an ideal candidate for adding a salt water chlorine generator to your pool. That automates FC addition and then you'll likely only have to keep a closer eye on your pH occasionally with muriatic acid additions.

 

[Mr Bruce]

GREAT JOB on doing homework, reading up and ordering a test kit! If everyone would!

Life will be much easier if you can drain some water. You'd really want to get down in the 70-80 range if you can.

I do have some bad news:

A little less than a gallon of bleach is fine but don't want to have to add that every week

The best you are going to ever get away with at any CYA and no automation and no SWG is adding every other day.

 

[tim5055]

Welcome to TFP!!

If the pool is clear you don't have a FC problem per se, it's just too low. With CYA 150 (it seems you did it correct) your FC should never go below 12 (7.5% of CYA) and I would target 15 to make sure.

The problems this leads to is that the pH test doesn't work properly above FC 10.

So, drain is your best option.

 

[Richard320]

Welcome!

You did the CYA dilution test perfectly.

Although you'll lose water to evaporation, you won't lose CYA that way. Some will be lost due to splashout, and some will be lost during backwashing the filter, but that's about it. It won't be enough to reduce CYA over the course of the summer.

If the water is clear, you could try maintaining it as-is. I know it is possible because I've done it, but it isn't easy and I don't recommend it. I didn't have a choice due to water restrictions.

It'll take a load of bleach to get up to target, but the daily FC losses will be no higher than they would be with a lower CYA level. You won't be using a gallon a day to maintain the higher level.

The problem with the high CYA is twofold
1) If you do develop algae, shock level will be higher than even the FAS-DPD tester can read. And the amounts of chlorine you'd need would be measured in barrels, not gallons.
2) Your minimum FC level is 11. The pH test is affected by FC above 10. Check the pictures. Your pH will always be suspect.

If you have the choice in the matter that I didn't, replace some water. It doesn't even have to be all at once. Lose a few inches a week and run it onto the lawn. I move valves and empty the spa into the pool, and while the spa is refilling from the hose, empty the pool back down to normal depth. Even reducing CYA to 100 will make maintenance a lot easier.

 

[tchap07]

Well, guess I will get to draining. Thanks for your help!

Regarding the SWG: I don't mind putting in the work and checking/maintaining every day. My main concern is the cost. Based on everyone's comments, it still looks like I will need to add a gallon of bleach every other day or so. $4.00 x 182 = $728 per year of bleach. Quick google search of salt water generators came up with one that costs $734. If I went the SWG route would that mean I could eliminate the cost of bleach every other day? Or do you have to add anything to SWG's to maintain FC? Seems like the SWG would be a no brainer if not. Anyone particular you recommend?

 

[Mr Bruce]

Not many of us swim year round, so it's more like mid April to mid September for me, shorter up North. With your pool you are probably looking at around 1/4 -1/3 bottle bleach per day in the hottest bit of summer.

Also, with regard to SWG, the cells die every few years, I think around 5-7 and they are expensive. So I think it works out about the same money-wise in the end.

 

[tim5055]

Well, guess I will get to draining. Thanks for your help!

Regarding the SWG: I don't mind putting in the work and checking/maintaining every day. My main concern is the cost. Based on everyone's comments, it still looks like I will need to add a gallon of bleach every other day or so. $4.00 x 182 = $728 per year of bleach. Quick google search of salt water generators came up with one that costs $734. If I went the SWG route would that mean I could eliminate the cost of bleach every other day? Or do you have to add anything to SWG's to maintain FC? Seems like the SWG would be a no brainer if not. Anyone particular you recommend?

Your numbers are a little high for the bleach. I'm not sure about McKinney, TX weather, but once the pool cools down in the winter the chlorine demand drops off considerably. Here in SC I end up adding every couple of weeks through the winter. Others have run the numbers comparing a SWCG to bleach and it generally comes out a wash. Over the limited life of the SWCG (they have a finite life span and need to be replaced every few years) you would have used about the same $$ in bleach. So, the SWCG really comes down to convenience and automation.

With salt system you have to add, well salt..... That's it

Your pH may begin to change a little, so your normal adjustment smay change there as well.

 

[Richard320]

Somewhere buried in the old thread archives there's one comparing costs. Over the lifespan of a SWG, it generally ends up about even whether you use bleach or a SWG. The SWG has the advantage of being automated. You can even leave town and the pool still gets chlorinated.

Shop around. You can find bleach a lot cheaper than four bucks a gallon, especially this time of year. Walmart's been selling some 10% stuff in the pool section for $2.50!

I use about a quart a day of 12.5% during the actual swim season for a similarly-sized pool. Less as the water gets colder. 10% would be about a third of a gallon. You're still at less than a buck a day if you shop wisely.

 

[JVTrain]

That number is high for sure as you'll use less in the winter and I can't remember the last time I paid $4 for a gallon of bleach, even the 12.5% stuff. Anyway... aside from bleach costs, SWGs I think make a lot of sense in pools that are open most of the year or all year. The only concern is with your coping or pool deck, especially in the Texas area. Flagstone (limestone or some sandstone) coping or pavers are not real fond of salt water. It can erode the stone over time if they are not rinsed regularly after splash out. Keep in mind a salt water pool is not ocean levels of salt. Sea water is 35,000 ppm or more. SWG pools are 1/10th of that at ~3500 ppm.

A Pentair SWG would likely integrate well with your controller, but I'm not much help in the automation department. Their SWGs are good but so are other brands such as Hayward or Jandy.

 

[bmoreswim]

Adding the SWG may cause your pH to rise on a consistent basis (I say may because each pool is different). So with a pool your size, you could see maybe a 1/2 gallon of 31.34% muriatic acid on your grocery list at $7/gal. each week, though it may be less or none. I use close to 1 gal per week during the summer, but my pool is x2 in size. There are other factors as well, but just factor in some expense for MA to the equation. All in though, it's roughly equal in cost going bleach vs. SWG over time.