haaaaaaard water

[lens]

Hello,

First, since this is my first post, let me just say thanks for creating such an awesome site! The pool school section is great for pool noobs like me. I just wish I knew about it and read it BEFORE I set up my new Intex pool and Intex SWG (model CS8110, the one with the copper ionization). Second, sorry for such a long post. Jason wanted data, so I'm trying to be thorough.

The story:
I filled the pool a week ago from our city water and this town is famous for having haaaard water. Anyway, I followed the Intex directions on setting up the pool and the Intex directions for setting up the SWG. The directions basically say, add 125 lbs of salt to the water (I saw a recommendation that you start by adding 75% on the Intex site, so I only added 100lbs and the generator seems to be producing CL with no error messages), wait 24 hours then turn on the SWG, set it for 4 hours, and run the "boost" mode (which runs the SWG full tilt for 4x the normal time, so 16 hours in my case) on the SWG to shock the pool. Well, after "boosting" the pool the first time, I didn't have any FC or TC (measured on sticks), so I set it to run for 6 hours the next night and no FC or TC again. I set it to "boost" again (so this time for 24 hours) and little to nothing the next day.

We've had great weather here and the pool has had bathers almost every day.

I was starting to panic, but the SWG was making bubbles and when I put a stick up to the return it did register FC and TC, but after a week I couldn't get it to last in the pool. Then I started doing research, and read on another site what CYA was, so I went and bought some (100% granules) today and added enough to the pool to get it up to 30ppm. I also saw that test strips were junk, so I bought the HTH 6-way test.

As I was doing that I noticed one edge of my pool had the slightest tinge of a brown ring up at the water line. The water is still crystal clear and not slippery or anything, but my neighbor last year had his water turn green twice (almost instantly) and had to refill, so I added 5 ounces of "Leisure Time Simple Spa Care 56 Chlorinating Granules" (Sodium Dichloro-s-Triazinetrione Dihydrate 99%) that I happened to have lying around (I don't have a spa, don't ask).

OK, so now the current facts:
pH - 7.2-7.5
TA - 220 ppm
FC - can't test
TC - 2-3 ppm
CH - 240 ppm
CYA - should be coming up to 30 this week with the CYA I added today plus some from the spa 56? I only get to test it one more time with this kit, so I'm waiting for the acid to dissolve.

So, what should I do to lower the TA and CH without tanking everything else? I have read that I can use Muriatic acid with a SWG, but not Dry acid. The pool calculator tells me I should replace 79% of my pool water with new 0 CH water, but that won't work for me as our water is hard from the tap.

Also, Intex recommended a CYA of 10 ppm, all the sites I have read say at least 30 ppm, and many SWG people seem to be running much higher, like 60-80 ppm. What should I do? I have plenty of CYA if I should add more.

Please help!

Thanks,
Lens

 

[daniel00]

I would diffently add mor cya, I have a intex swg and I have my cya at 60-70. With a lower cya your are going to loose more chlorine. Just so you know a pool will usually loose 1-2 ppm per day of chlorine. On another note keep an I on your plates in the swg, if you have hard water you will have to soke them in vinager about every other month or so do to build up on the plates.

Daniel

 

[duraleigh]

Lens,

Welcome to the forum!

YOur CH of 240 is virtually perfect....there is no need to adjust it.

Bring your CYA to 60 or so as suggested. YOur FC will stay in the pool longer.

Stop using Di-chlor...ever. If you need to supplement your SWG while your balancing things out, use clorox.

Elevate your FC up to around 3-5ppm and keep it there never letting it get below 3ppm.

There's an article in pool school on how to lower TA but I put this suggestion last because I believe you should get YOur chlorine and CYA issues fixed before you make any attempt to adjust TA.

 

[zea3]

240 actually is not a bad number for CH. If you read through all the articles in Pool School, the page on recommended levels states that with a vinyl liner and SWG you can have CH up to 300 ppm. I don't know why they would say not to use dry acid, but MA is fine and usually less expensive, just be careful and pour it slowly in front of the return with the pump running. Wait about 30 to 60 minutes before adding any other chemicals. Normally I would advise you to buy the Taylor K2006 or TF 100 test kit, but since you already have the hth 6 way, I would advise you supplement it with the FAS-DPD chlorine test and the CYA test from TF test kits. The FAS-DPD chlorine test is essential for testing chlorine levels greater than 5ppm. Since we don't want to overshoot your CYA, after a week has passed test it again and add enough to get to 60ppm total CYA.
Since we lower TA by lowering pH then raise pH back up with aeration, you will likely need to repeat this process several times. Do you have a fountain? Above ground pool fountains are inexpensive and fairly easy to find. Or you can make an aerator like this, this, or this. You can also try pointing the return up so the water breaks the surface. You want the "churning" effect to the water as seen in the aerator examples.

 

[lens]

Thanks everyone!

I'm very glad to hear about the CH not being an issue. I'm not sure how I missed that, but thanks for being gentle.

OK, I think I have a plan now:
1. We had some old 2004 Clorox Ultra bleach laying around so I'll increase the run time of the SWG and add that bleach as neccessary until stabilized. Get and keep my FC up to 3-5 ppm.
2. Give the CYA a few more days to absorb (the granules in the sock were completely gone and I removed it, but I guess everyone is talking about some sort of invisible chemical process?), then test and add more to get CYA to 60-70 ppm, and buy the remaining test kits and refill I need.
3. Aerate to get my pH up to 7.5-7.6.
4. Once everything stabilizes, I'll bring the TA down with Muriatic acid if I need to.

On aeration, my return can point up, and is close to the surface, and it looks like it is creating some bubbles, but not like the examples from the home mades. That does bring me to another question though. The default Intex pump for this pool is 1500 gallons per hour (and has the type A paper filter attached), and seems to put out very little pressure (the SWG and hose to it add less than 4' to the hose run). On reading the Intex site (and here), the pool kits are notorious for really weak pumps. What would you recommed as a replacement? I guess I would need a filter and pump, since they are attached?

Thanks again!

P.S. I forgot to mention that I've been running the pump 24x7 since I put the pool up on my neighbors advice, and clean or change the filter frequently, and skim daily. We have several huge mulberry trees in the area that drop leaves and berries in the pool frequently.

 

[duraleigh]

6 year old Clorox will have virtually no strength left. I wouldn't even bother using it.

 

[zea3]

Many intex owners find good deals on used pumps and filters on craigslist and ebay. You would want a 1/2 hp pump and a sand, cartridge, or DE filter. Most people feel sand is less trouble, but DE filters finer particles from the water. I wouldn't go over 1 hp on the pump.
You can dump the geriatric clorox in but it won't do much. Walmart has their great value 6% bleach 96 ounce jugs for $1.27. The most expensive I've found for the same size jug was around $2.00. Be sure to get plain, unscented bleach!