Muriatic Acid vs. Dry Acid for Spa

[BigOrangeSpa]

Good afternoon,

I am getting ready to purge my spa this weekend with Ahh-some and start using the Dichlor/Bleach method described in the sticky. I also plan to use Aqua Clarity once a week. I'm hoping to drag my water changes out to 6 months with Aqua Clarity.

I've been using Dry Acid to lower Alkalinity and pH on previous fills. I've been reading about Muriatic Acid and the advantages it has over Dry Acid -- mainly not contributing to sulphate buildup. I usually need a large amount of Dry Acid to get my TA and pH under control after a new fill. My TA from the tap is around 250.

Given the large amount of Dry Acid needed, and the length I hope to keep my water, is it worth switching to Muriatic Acid or is the buildup of sulphates not particularly important with water changes every 6 months? If I do switch to Muriatic Acid, I'm still a bit unsure how exactly to add it to the hot tub to prevent issues. I'm reading conflicting opinions on diluting it first versus adding it directly. Should I run the jets and pour it slowly in the middle of the hot tub?

My local Ace has full strength 31.45% Muriatic Acid that I'd be using if I switched to it.

 

[PoolStored]

With the extended time period you are shooting for, and the high TA, I'd switch to muriatic acid.

Do not dilute it first. Reduce the times and time you handle it. Yes, run the jets and pour it slowly in front of a jet (6-12" out). Should be fine.

Someone will check my math, but 1lb of dry acid will add about 240ppm of sulfates to your 400g tub. Anything over 200-300 starts to become an issue.

 

[BigOrangeSpa]

Oof. I was well over 21oz of Dry Acid for my last fill.

 

[BigOrangeSpa]

One other question if you don't mind, should I spread out the Muriatic Acid to bring down TA over several days or is it okay to dose, aerate and then immediately dose again after aeration brings pH back to 7.8?

 

[PoolStored]

This might help you...

Lowering Total Alkalinity (TA) Quickly with the Acid Aeration Method

Thought I'd make a post that might help others. We've had quite a few members this year with high TA, and I've been typing the same information over and over. I'm going to post this so I can link it to help others. High TA can cause rapid pH rise. High TA is typically caused by high TA fill...

www.troublefreepool.com

 

[redalert001]

I would definitely recommend switching to muractic acid I just did it this week on Wednesday. I was scared but it wasn’t too bad at all! I had a TA of 240 and it was much easier than the dry acid. I also put way too much dry acid in on my last fill so that’s why I had to dump the water and start over as I was fighting the extra aeration from the ozonator. The dry acid took way longer for me I wouldn’t do it again. I would buy a plastic oxo measuring cup as that’s what I used to measure as the ounces you will need to measure will be less than 1 oz sometimes. Make sure the oxo measuring cup is the smallest version. I also bought a plastic oral syringe from Walmart I haven’t tried it out yet but I thought it would be easier than trying to pour acid into the oxo measuring cup with the oral syringe I could pull the acid out. Again, I have not tested the syringe yet it was only $3 so nothing to lose.

I just switched over so if there’s a better way to measure the muractic acid for a spa (275 gallons) I am open to hearing from the long haulers here.

 

[BigOrangeSpa]

Thanks! I was able to switch over and used Muriatic Acid after the refill. Not nearly as bas as I was thinking and glad I made the switch. I just poured it into a plastic measuring cup and it was definitely hard to measure the smaller amounts as the TA dropped. I will look into the oxo measuring cup!

 

[redalert001]

Thanks! I was able to switch over and used Muriatic Acid after the refill. Not nearly as bas as I was thinking and glad I made the switch. I just poured it into a plastic measuring cup and it was definitely hard to measure the smaller amounts as the TA dropped. I will look into the oxo measuring cup!

Glad to hear it!

 

[RDspaguy]

The reason muriatic is not recommended for spas is mainly to prevent damage from spills or mis-use. If you pour it in the same spot near a side you WILL get damage over time. Discoloration, deteriorated rubber/plastics, etc. Dry acid is just more forgiving and easier to clean up.

 

[cybernation]

The reason muriatic is not recommended for spas is mainly to prevent damage from spills or mis-use. If you pour it in the same spot near a side you WILL get damage over time. Discoloration, deteriorated rubber/plastics, etc. Dry acid is just more forgiving and easier to clean up.

I thought it was frowned upon from pool stores trying to get your $$$ for ph down .... for real (can't say anything about spas, but i used muriatic acid for years in the pool). Now i have a giant spa.

 

[RDspaguy]

Spa warranties specifically exclude liquid chemicals, not just acid. You void your warranty by using them. This decision undoubtedly resulted from warranty claims for damage caused by liquid chemicals. I have seen what can happen in extreme cases. With a little knowledge and a tiny effort it's fine. I use liquid myself, both chlorine and acid. But you can do damage, even in a pool. Show me a 5 year old plaster pool and I'll show you where the owner stands to pour in the acid if it's the same spot every time. Ditto for a concrete deck. I'll tell you where the dead spots that trap the floater are too.

 

[BigOrangeSpa]

Spa warranties specifically exclude liquid chemicals, not just acid. You void your warranty by using them. This decision undoubtedly resulted from warranty claims for damage caused by liquid chemicals. I have seen what can happen in extreme cases. With a little knowledge and a tiny effort it's fine. I use liquid myself, both chlorine and acid. But you can do damage, even in a pool. Show me a 5 year old plaster pool and I'll show you where the owner stands to pour in the acid if it's the same spot every time. Ditto for a concrete deck. I'll tell you where the dead spots that trap the floater are too.

It's interesting because when I was reading my manual I ran across the section that talks about the warranty in regard to chemical usage and it said "This warranty is void if this Tropic Seas Spa™ has been subjected to alteration, misuse, or repairs have been performed by anyone other than an authorized agent of May Manufacturing, LLC. Misuse or abuse is defined as: use of the spa in a nonresidential application, water temperature outside the range of 32 °F to 110 °F, damage caused by clogged or dirty filter cartridges, damage to the spa from an absence of a hard cover, damage to components from improper pH, use of any type of acid, or from chemical imbalance. ACTS OF NATURE are not covered under this warranty."

I contacted the dealer and asked how it could forbid any type of acid since they provided me with pH down. I was told that it means that damage caused by any type of acid isn't covered under warranty, but use of acid itself doesn't void the warranty. I also asked them about liquid chlorine and they said the same thing: using it won't void my warranty but improperly using it will cause them to not warranty whatever is broke because of it.

I was happy with their response as I was nervous to void my warranty.

 

[RDspaguy]

It's interesting because when I was reading my manual I ran across the section that talks about the warranty in regard to chemical usage and it said "This warranty is void if this Tropic Seas Spa™ has been subjected to alteration, misuse, or repairs have been performed by anyone other than an authorized agent of May Manufacturing, LLC. Misuse or abuse is defined as: use of the spa in a nonresidential application, water temperature outside the range of 32 °F to 110 °F, damage caused by clogged or dirty filter cartridges, damage to the spa from an absence of a hard cover, damage to components from improper pH, use of any type of acid, or from chemical imbalance. ACTS OF NATURE are not covered under this warranty."

I contacted the dealer and asked how it could forbid any type of acid since they provided me with pH down. I was told that it means that damage caused by any type of acid isn't covered under warranty, but use of acid itself doesn't void the warranty. I also asked them about liquid chlorine and they said the same thing: using it won't void my warranty but improperly using it will cause them to not warranty whatever is broke because of it.

I was happy with their response as I was nervous to void my warranty.

I guess they can be taught!
I've worked for a dealer of a brand that used to be notorious for warranty games and have seen warranties voided over corroded heater elements. That was many years ago, but I suspect there are still those that do the same now.