Steps in adjusting pool chemistry

[halds]

Greetings TFP members!

I just joined the group, and am reviewing the 3B's. I am getting ready to open the pool, have my testing kit in hand (except for the borate strips, which I will get soon, did not realize they were not included in most kits...) and chemicals.

I am familiar with the various tests needed to be done and the recommended ranges. However, I find that the instructions provided (here and elsewhere) do not go into detail about what steps should done in a certain order. Is this important?

I would imagine shocking and then stabilizing FC at 2-3 ppm and CYA at 20-30 is foremost. But from there what is next? Adjust the pH or the TA next? When do I adjust the borate to 50 ppm? It would seem that the order in which these 3 steps are done is important and would influence each other?

Just a little confused about this. Could someone set me straight?

It is fiberglass pool so CH is not a major issue, although our water tends to be hard to begin with.

 

[JasonLion]

Most of the constraints on what order you do things in involve CH. There are really two remaining interactions. If TA is very very low you should work on TA before PH. Also, you want to get PH between 7.2 and 7.8 quickly before working on chlorine, but if that ends up taking more than an hour or two go ahead and start on the chlorine without waiting.

Other than those constraints, various orders will work, and you can almost always work on everything more or less at once. Here is a suggested order:

If TA is below 30, start adjusting TA first, otherwise wait.
Get PH to between 7.2 and 7.8.
Add some chlorine.
Start working on CYA.
Continue adjusting everything as needed.

Keep in mind that it is best to adjust everything except chlorine in several steps, so it may take a couple of days to reach your target levels, weeks for CYA. Also, chlorine needs to be added regularly, while most of the other numbers will tend to stay close to what they were before.

 

[halds]

Thanks for the good advice!

Is there any way of estimating what adding 50 ppm of borate will add to the TA?

seems if I adjust the TA to 120 first, then adding borate to 50 ppm could send TA over the cliff?


thanks

 

[chem geek]

Adding 50 ppm Borates (and Muriatic Acid to maintain the pH) will only increase the TA by 5.2 ppm at a pH of 7.5 and this is independent of the starting TA value. The Borate pH buffering has more capacity against a rise in pH rather than a drop in pH while TA measures the buffering capacity against a drop in pH.

 

[257WbyMag]

If you follow waterbear's borates procedure in the stickies, the effect on your TA will be minimal. When adding borates you also need to add acid simultaneously. When I added my borates a couple of weeks ago, my TA only increased slightly from 70 to 80 by the end of the process.

Craig

 

[halds]

Thanks again.

I understand better now.

 

[Guest]

FYI, CH IS important in a fiberglass pool. There is some evidence that having CH in the proper range will prevent cobalt leaching from the gelcoat (cobalt spotting) and may help prevent iron staining.