Cyanuric acid?

[CalicoskiesNC]

I only know a tiny bit about cyanuric acid and I'm not sure what I know is even accurate or relevant. Its a stabilizer used in chlorine, right?  So if you use dichlor in your spa, do you have to be concerned about the CYA level?  Is the CYA a byproduct thats in the dichlor and then becomes a residual in the spa water?  If so, how do you test...with strips (which I dont trust) or a drop test?  Is this a real concern for spa owners becuz I dont hear much about it.  But being that I use dichlor daily and weekly as my shock, I'm now concerned about it.  Thanks for any clarification.

[Chas]

If you change your tub's water every three or four months you should be fine.  Before the CA gets too high the TDS is usually up there anyway.

There is a tester just for Cyanuric acid, if you want to test for it.

[windsurfdog]

Calico,
Yes, cyanuric acid is a part of dichlor and will accumulate in your tub.  I think it is much less of a concern than TDS--in other words, I think you will be more prone to do a water change because of TDS than cyanuric acid accumulation--especially if you switch to MPS as a shock.  I'm trying to KISS as you mentioned in another thread by using only the chems needed.  MPS is not needed if using dichlor.  It's more expensive and yet another chem to stock.  BTW, if you have a Taylor Test kit, there is a test for cyanuric acid included.  I've never tested for it--haven't seen the need so far especially having completed my first water change after about 5 weeks of use.  I may be more prone to test for it if/when I go longer between changes.

[windsurfdog]

Chas,
Looks like we posted together and I'm sure glad we agreed!  I am but a grasshopper....if I can pluck the rubber ducky from your hand, I too may one day be a master......

[Chas]

"Expect the unexepected."

[SerjicalStrike]

After reading a few articles online, it seems as though CYA is more of a problem than TDS.  Here are a couple of links.

http://www.ppoa.org/pdfs/PrP_Cyanurics%20-%20Benefactor%20or%20Bomb.pdf

http://www.ppoa.org/pdfs/What%20is%20the%20Fuss%20Over%20Total%20Dissolved%20Solids.pdf

George

[Warkovision]

Calico,
Yes, cyanuric acid is a part of dichlor and will accumulate in your tub.
 

I was curious about this. We have a service that uses chlorine gas in our pool. The advantages being (as I was told) that all the stableizing stuff doesn't come into play. Are hot tubs just too small for this method? Given the fact that depending on usage, more would have to be added, I would think that a do-it-yourselfer wouldn't be able to do this without creating a W.W.I. condition of some sort. That tube from the chlorine gas tank must only be in our pool for about 30 seconds every week.

[Chas]

The chlorine gas going into your pool must be IMMEDIATELY and thoroughly neutralized: or more correctly, the acid condition it forms in your water must be adjusted at the same time the gas is going in. Watch them some time: they should weigh the tank to put in a set number of pounds of gas, and then throw in soda ash or similar before many minutes' time elapses.

Then, of course, they close the pool to bathers and shut off the timeclock so the acid doesn't damage people or equipment.

There are people who go on big rants over the 'shooters' who put pure chlorine in gas form into pools. They are becoming more accepted in the pool service community, but they were pariahs for many years.

[windsurfdog]

You can take away my dichlor when you pry it from my warm, wet hands.........

[Warkovision]

Interesting. We've been using this company (Pool Chlor) for 17 years with no problems whatsoever. Or at least I think so. I have seen them throw in a tupperware tub  of some white powdery stuff on occasion. Not to say that they don't do this every time. I've only observed it a few times.

[CalicoskiesNC]

Ok, from what I surmise here...as long as I change my water every 2-3months I will not have an acid bath cooking out there.  We use our tub every day, almost always its all 5 of us and 3 are kids, so I dont think I'd ever be able to go longer than 8wks without a change of water, just cuz in my mind I'd have visions of it being a cootie cesspool and besides, fresh water is sooooooooooo nice.  Here in Raleigh NC its costing me less than $3 to fill up.

[SerjicalStrike]

The best thing for your tub is fresh water.  You almost have to think of it as a big bathtub.  After between 75 and 150 bathers, the water will start to get tired and then it is time to change.  

[tony]

Agreed.  Fresh water is wonderful.  Dichlor has a high level of CYA.  

Here is a comparison showing free chlorine levels needed at different CYA levels from Pool Solutions.

CYA  Min FC  Max FC  Shock
0          1        3        10
10-20     2        5        12
30-50     3        6        15
60-90     5       10        20
100-200  8       15        25

I just changed my water this last weekend and CYA levels were way over 100.

[tony]

I have been a huge supporter of N2 with dichlor and shock with chlorine.  I am not abandoning this but I believe CYA has to be watched and when it gets to certain point, it is time to drain and fill.

[Vinny]

Like Tony, I've been at Pool Solutions and CYA is a big deal in pools with it's effect on chlorine against algae (I've seen it in my own pool)

I think the main difference between pools and tubs is that pools have to deal with algae along with bacteria and tubs have to deal with mostly bacteria. Is it possible that bacteria is easily killed vs algae so a higher CYA doesn't render lower doses (2-3 PPM) ineffective.