High CYA, Low CH... Which first?

[bigdognj]

This is my first post at TFPC, so I would like to thank everyone for all the help I've received while lurking for the past year.

Here are my current chemistry results: FC 6.8 TC 7.5 pH 7.5 TA 119 CH 94 CYA 70 (I just got my Lamotte test kit and am so happy to be rid of test strips forever)

Last year because of faulty test strip readings I added stabilizer to the pool when it wasn't needed. I've been working at slowly reducing the CYA level from well above 120 by frequent backwashing and filling and maintaining FC with cal hypo 73%.

As a consequence, CH has now dipped below 100. I am a little reluctant to add calcium chloride until I get the CYA down to 40 or 50, which could take another week or two. I just don't want to be flushing away $50 worth of chemicals.

Will my plaster pool be OK during the process, or do I need to add the hardness increaser right away to raise the CH to 250?

For similar penny pinching reasons, I would prefer to use up my substantial stock of trichlor and dichlor. Will using these products result in overstabilization again?

 

[Casey]

Welcome bigdog.

I would suggest you do another partial drain/refill to get your CYA down and then, once in range, get your pH where it needs to be, add your FC and then, when everything is looking good, add the CH.

You wanting to pinch pennies and use your tri & dichlor will put you back in the same position you are now. Ask yourself if using the stuff is worth the cost of water and the time you're losing out on swimming.

Also, run a search on the LaMotte test kit on TFP. You should get a better test kit than that. Look at these :arrow: Test Kit Comparison. The TF100 is the best kit for the money as you will get more reagents and both of the kits will check FC up to 50ppm.

 

[bigdognj]

Thanks, Casey.

I will follow your advice on how to proceed. Is my thinking right about a CYA target of 40-50ppm? My pool gets substantial sun.

I am reluctantly resigned to giving up on the dichlor and trichlor if they are going to cause me to have to go through all this again. I guess I'll be pouring bleach for the foreseeable future.

In re the test kit, I got the Lamotte despite the ambivalent reviews on TFP because, I confess, I am addicted to gadgets. Also having read the instructions for the two kits the Lamotte just seems so much easier to use and much less subjective. So far, I've been getting highly repeatable results and my additions of chemistry (based on Pool Calculator calculations) have turned out exactly as expected. It's hard to ask for more. Nevertheless, I'll probably invest in a TF100 for periodic accuracy checks and for a sanity check on the CH results I'm getting in particular. Oops... just ordered one

 

[jblizzle]

Well, hopefully you will not be like the many other members who loved the Color Q for a month and then come back and throw it away due to unreasonable and unreliable results. I would never trust them ... you have never had a piece of electronics suddenly go bad? How do you plan to keep it calibrated? I know when I count the same number of drops the chemistry is the same. Do you KNOW that the highly precise numbers are correct?

Of course the first time you get algae (hope you don't, but it can happen to all of us) and need to follow the SLAM process, you will quickly be up a creek as the Color Q only can read up to a FC of 10ppm which is not nearly high enough.