please validate my borating plan

[Diver]

I have a 30k pool and I’m planning to add some borates to it using boric acid. I plan on buying 80lbs of boric acid from dudediesel and add about 70 lbs of it plus about 5 lbs of borax (93/7 ratio). That should bring borates level to 50ppm without affecting PH (TA?).

My PH is 7.4 and TA is 130-140 right now. I know the approach is to have TA lower before adding borax, but since I’m going mostly boric acid, I assume it should be ok. Am I right here?

I plan on adding the rest of boric acid (10lbs) at the end of the season to compensate for backwash and bring it to 50ppm before closing. 10lbs is about 14% of initial load, so it should be somewhere around 50ppm.

I was thinking about buying borate strips for next year since this year should be ok by calculation only. However looking at some pictures posted here of borate strips it seems that it’s really hard to judge the levels of borates by the strips. So I wonder if I could simple up the levels by 15% at the end of the season for couple of seasons? Is it a bad idea?

Also do borates get consumed thru the winter or do they stay?

 

[JasonLion]

I wouldn't bother adding any borates at the end of the season. It is much better to do that at the start of next season.

It is tricky to calculate exactly how much borate you lose over the course of a season. Despite their problems, the borate test strips are better than guessing.

Using a mixture of boric acid and borax doesn't have anything to do with lowering TA. Since you don't have a SWG, lowering TA is not such a big deal, but still best to do beforehand.

We have never seen the borate level go down over the winter, aside from the water replacement from winterizing.

 

[Diver]

Jason,

my idea of adding at the end of the season is to compensate for loss due to backwash and go into closing fully borated to further prevent any possible algae problems. since it doesn't go away in the winter why do you think it's better to add in the spring?

 

[bobodaclown]

less change of algae issues in winter due to colder water.

 

[JasonLion]

The borate level over the winter is not especially important. The water is cold and dark so algae doesn't grow all that well anyway. Also, if you do winterize, some of the borates you just added get instantly pumped out when you lower the water level for winterization, which is wasteful.

 

[chem geek]

If you want to prevent algae growth when winterizing your pool, then close as late as possible so that the water is cold (< 50ºF, the colder the better), shock with chlorine and then add PolyQuat 60. During spring, open the pool as early as possible when the water is still cold (again < 50ºF) and you should find that little or no algae has grown in the interim.

 

[Diver]

guys, thank you for your responses.

i wasn't looking to add borates before closing to fight the possible algae, but rather to compensate for loss during the season. and since it doesn't go away during winter i was thinking about it would have a small additional benefit of borates being light algae deterrent. and since it doesn't go away in the winter, then why not?

as Jason stated, there is a downside of wasted chemicals due to pool draining before closing. but the same can be said about shocking before closing. both issues could be addressed by draining, adding chemicals and then manually mixing it.

thank again for your responses.