How much Dry Acid (Sodium Bisulphate)

Denniswiseman · Postby **Denniswiseman** » Fri 14 Oct, 2011 13:28

I have managed to get my TA down to 100ppm & 7.4PH using the acid/aeration method.
I would like to let you know that the pond aerator worked a treat and I would recommend it as an alternative if you don't want to cool the water.
I run it all night with a thermal cover on then I remove the cover in the morning.
It is cheaper to run than the filter pump

Postby **chem geek** » Fri 14 Oct, 2011 19:19

Thanks for letting us know. I'm surprised this worked with the pool cover on but perhaps the air was able to escape from under the cover since it has to go somewhere. When one wants to prevent pH rise from outgassing, one can put on a pool cover, but in that situation one is not injecting air into the pool.

Denniswiseman · Postby **Denniswiseman** » Fri 02 Mar, 2012 09:23

Hi

I am now completely over to Liquid Chlorine, Hydrochloric acid and Aerating.
All are working well but I have a few questions

Does Sodium Hypochlorite increase TA at all, as mine seems to be rising with no other chemicals being added
Is is OK to pour the Liquid Chlorine and the acid in the skimmer while pumping
I'm pouring it in over the return eyeballs at present but feel it would get a better distribution through the filter system

Postby **chem geek** » Sun 04 Mar, 2012 12:53

Sodium hypochlorite (chlorinating liquid or bleach) has some excess lye in it so can slowly increase the TA over time, but how much depends on the specific product you are using. 6% Clorox bleach has the least amount of excess lye in it so has minimal net pH and TA rise over time -- it has a pH of around 11.9. Some off-brand bleaches have a pH of 12.5 or more. Good 12.5% chlorinating liquid has a pH of around 12.5 while some lesser brands have a pH of 13.0 or more.

The TA can also rise from evaporation and refill with fill water since fill water has TA (and usually CH as well). If you find that your CH is also slowly increasing, then it's more likely to be evaporation and refill.

In general, you do not want to pour concentrated chemicals into the skimmer. This is most certainly the case with strong acid since it can damage pool equipment such as heat exchangers and pump seals. Chlorinating liquid or bleach won't be as damaging but it's still not a good idea since it is a strong oxidizer, certainly not to do on a regular basis. Baking soda and cyanuric acid are OK to put into the skimmer (the CYA will get caught in the filter and slowly dissolve there). If you pour your chlorinating liquid or bleach slowly over a return flow with the pump running, it should get reasonably mixed. You can lightly brush the side and bottom of the pool when you are done if you think it doesn't circulate well enough. If you pour in front of a return that is opposite a skimmer and/or above a floor drain, then the chlorine will go back to the pump (diluted) and come back into the pool via other returns.

Denniswiseman · Postby **Denniswiseman** » Mon 05 Mar, 2012 05:26

Hi

I'm using Sodium Hypochlorite 14-15% so I expect it will be a lot higher. I don't have a lot of top up water so it must be the chlorine raising it

I won't pour into the skimmer then otherwise all seems OK

pastorestong · Postby **pastorestong** » Wed 29 May, 2013 05:06

Dear sir,it was a wrong purchase order,becouse im using sodium bisulphate,but the delivery was sodium metabisulphite.my question is ,can i use it in our swimming pool to control the ph? I appreciate for your time.thanks.