water chemistry 101

[anne]

I have searched a ton of entries in this forum over the last 2-3 months to educate myself about water chemistry. I have a bit of a science background, but I'm not a chemist. However, it drives me nuts to not UNDERSTAND products that I'm using, so it is important to me not to just memorize what people recommend, but to actually understand, in lay terms, what is happening in the water. So, is this about right? Please dont laugh, and please correct me if I'm full of S*!!#.......

Sanitizers= Chlorine, Bromine, Biguanide. Needed to kill organisms.
Total Chlorine= Free Cl (FAC)+Combined (CC). The "free" is doing it's job sanitizing, while "combined" is residual in an organic form, such as chloramine. We want to get rid of CC by "shocking"

"Shocking"=oxidizing. Here's where I get confused, cuz it seems that you can shock with MPS (peroxymonosulphate), a strong ozidizer, or with a high dose of chlorine which is NOT that strong of an oxidizer....?

Minerals help- not sure how- but are used with sanitizers as a supplement to help purify the water and reduce bacteria and algae. Nature 2 is an example. Nature 2 apparently should not be used with Bromine or Biguanides. Do they form bromine or guanine compounds that are bad juju?

Enzymes Such as Eco One and Spa Perfect ezymatically break down organisms and organic compounds. Where these broken down parts go is still a mystery to me.

Ozone is an oxidizer, obviously a little controversial in its application here, since it is so unstable, difficult to measure, etc.....

Mineral and enzyme additives, as well as ozone, are attractive in that they reduce the amount of sanitizer needed to keep water safe, so people smell less Cl or Br and feel less like they are in chemical soup. But then how do you know how much chlorine to use? Do you change the target level of chlorine in terms of ppm?

TDS=total dissolved solids, and represents *everything* in the water that is not H2O. With any added product, especially MPS, you are contributing to TDS, therefore may have to change your water sooner. Thus the appeal for dichlor as a "shock".....even though it is a les effective ozidizer.

pH should be maintained between 7.2-7.8, though the higher the pH, the less effective chlorine is as a sanitizer. Sodium bicarb is added to increase both alkalinity and pH; CYA or cyanuric acid is used to reduce pH. I read somewhere that dichlor contains CYA to protect the chlorine from the sun? (ie, for swimming pools?)

Alkalinity should be kept at 80-120 ppm. What puzzles me here is that I dont get how pH and alkalinity can be manipulated separately. pH is just a logarithmic scale representing the concentration of H+ ions. If something is more alkaline, there are fewer H+ ions, and vice versa.  And what is being measured in ppm? bicarb ions?

Clarifiers must remove solids somehow, as the name implies, but I dont know what they are chemically.

Can anyone answer some of these questions? If anyone can add to this summary or correct me, even more fantastic. Thanks for your time.

[tony]

You've done a pretty good job.  Not many questions.  I'll try with a few.

Shocking:
Actually chlorine is a strong oxidizer.  It does an excellent job and at one time before MPS was used almost exclusively.  Shocking a chlorine spa with chlorine means adding enough to reach breakpoint chlorination.

Minerals:
I think the copper in the N2 cartridge will react in a negative way with bromine.  A similar cartridge made by King Technologies called the Frog can be used with either chlorine or bromine.  Not sure about what happens with either in water sanitized with baqua.  Minerals, particularly silver, breaks down the outer coating of bacteria cells making a low dose of sanitizer able to "finish the job."

Enzymes:
These do more than break down organisms and organic compounds.  They essentially eat them.  Wastes are filtered out.  One of the important tasks while using enzymes is to clean filters weekly.  Enzymes like a slightly high pH, also.

Ozone:
This is a powerful oxidizer and santitizer.  The problem is the amount of contact time in a large enough body of water such as a spa.

Most target levels of chlorine or bromine with the use of minerals or Eco One are about .5 ppm.  With chlorine, it is difficult to maintain any level, thus the dose after use and let it drop routine.  The dose should be enough to get to 2 ppm and it will drop to zero.  Without a helper, you would want to dose to 3+ppm, but the biggest advantage is when the free chlorine level drops to zero, the water stays protected for a longer time.

TDS is affected so much by MPS, because MPS is added at doses that are substantial and regular.  Another example of something adding to TDS is the use of lithium, a type of chlorine acceptable for use in a spa.  It comes in granular form and is 35% chlorine by content with 65% other inert ingredients.  Regular dosing with its mostly other ingredients will add greatly to TDS.

CYA aka stabilizer is used to protect chlorine from the sun.  It is not needed in a spa because the spas have covers on them most of the time.  Dichlor is half CYA.  It is ideal in a spa because it is quick dissolving and has a neutral pH.  Dry acid is used to lower TA and pH.

Everything that enters the water will affect pH.  Alkalinity increaser or baking soda, sodium bicarb, will raise pH also because it has a pH of around 8.  Dry acid lowers both TA and pH.  Soda ash will raise pH while not affecting TA.  Adjust TA first, then pH.

Clarifiers clump together tiny particles that are too small to filter enabling them to be, yes, filtered.  Clarifiers to a great job of clearing up problems such as hazy water that doesn't come sparkling clean.  I don't recommend use of them on a preventative maintenance basis.  Enzyme additives such as LeisureTime Enzyme are better for that.  I have gone through one bottle of clarifier in almost four years, but you gotta have it around because when you need it, it works.

Hope this all makes sense.  It is getting late.

[Tman122]

Very good Tony.

I would also like to add that water balance (PH, TA, calcium hardness, metal) are one thing and perfectly balanced water will have in range numbers of these items.

Sanitizer is a completly different thing and you need it to keep bugs and nastys from getting in your water.

One affects the other and both need to work together for great water.

[Tatooed_Lady]

I'm impressed....I don't care what everyone says about you guys, you're SMART!  
I like the bit about only having used a tiny bit of clarifier over the last 4 years..my dealer said she's only had to order the stuff for the store twice .....in FOUR YEARS.

[Snowbird]

Here are two links to sites that I found helpful.

http://www.rhtubs.com/store/proNcon.htm
and
http://www.rhtubs.com/store/waterhelp.htm

[ssbraun]

Anne and Tony...great summaries!!  This should help lots of new spa owners.  Anne, you probably know this part, but since you said you were a bit confused I thought I'd add it JIC...MPS as a shock: tub can be used 15 minutes later...dichlor as a shock: you will likely need to miss a day of tubbin' while the chlorine ppm drops to 5 ppm or less.  That's why many use MPS.  Others use dichlor to shock because of the heavy hit of sanitizer that happens with shocking, or the reduced TDS that they add, or they have a skin reaction to MPS.  Hope this helps

Steve

[anne]

Tony and Steve, thanks for filling in the blanks and ansering my questions! Snowbird- yep.....I found that site literally minutes after posting my newbie-summary. Very helpful. Still glad that I did my own searching, though, since I think I will
remember it all better.

thanks!
Anne

[hottubdan]

All I can add is the EPA does NOT consider ozone a sanitizer.  Great oxidizer, not a sanitizer.

BaquaSpa and other biguanides do not react well with metals.  Therefore, there is bad juju when used with mineral cartridges.

[hottubdan]

Anne,

What system are you planning to use?

[anne]

I think I'm going to start with dichlor and Nature 2 (or another mineral cartridge), and my spa will have an ozonator. I'm making those choices just based on how many people here seem to be happy with that combo. I think bromine irritates my skin, based on wet testing. I may be wrong- it just may have been due to sitting in a number of tubs over a short period of time with different chemical conditions. When i was a kid, we had a redwood tub with one or two jets- my dad built the whole thing. I was in that tub all the time, and never bothered by chlorine.

[hottubdan]

Good choice.

[Spatech_tuo]

I think I'm going to start with dichlor and Nature 2 (or another mineral cartridge), and my spa will have an ozonator.

VERY good choice.