Cya levels

[darbyj62]

Thanks again for all the good information on the board. It has helped tremendously on the pools I take care of.
Quick question about CYA levels.

The pools look great, finally getting all the levels in proper areas but I notice that it is recommended to keep CYA levels at 60-70 for saltwater pools.

Right now the levels are 35-40.

Free chlorine level range between 5-6 but never really go down, in fact I have the SWG's turned down to 15% and it still is tough to keep the chlorine levels down.

Part of this, is because the pools have automatic covers that are closed whenever the pools are not being used. The pools get used maybe 2-3 times a week, so burn off of chlorine is pretty minimal.

My question is is it necessary to get the CYA level up to 60? I can only imagine that at that level it will be even harder to keep the chlorine level down as it won't burn out a lot.

I also understand that every pool is different. At this time the pumps have been adjusted to keep them running enough to keep the pools clean and sparkly but short enough to not keep the SWG's running even more.

The pools are 11,000 gallon with goldline controls and t-15 cells.

Again thank you for the valuable resources and information from everyone.

 

[MattM]

No, it's not absolutely necessary to increase cya levels to 60. Some people run their pools perfectly fine with CYA of 30 - it will depend on how much sunlight, bather load, and other organics enter your pool. Note however, that SWG and CYA isn't a one time setup -- it's ongoing maintenance -- the recommendation for 60 seems to be because that produces the least 'surprises' long term. As your pool heats up over the summer, it will require more chlorine or higher cya levels....if you let FC drop too far just once, you could develop an low level ongoing algae problem that your SWG will have to continously fight against. SWG's are much less likely to have such issues happen with higher CYA levels. I initially tried to get my pool working with 30 cya but ended up having to shock too often....also cya levels would not keep steady at low levels or be as easy to test....increasing CYA to 40+ made a world of difference. 30 is probably the minimum, 40-50 the sweet spot, and 60 the safest. Feel free to make your own choices.

 

[Isaac-1]

Many SWG pools have undersized saltwater generators, which can't keep up with the demand, also the less you run your SWG the longer the plates tend to last. The 60-70 ppm CYA level allows for a minimal demand on the SWG in typical pools, having said that since you have an automatic cover and therefore low sunlight exposure, you should have no problem at your current CYA level.

Ike

p.s. I have an indoor pool and keep my CYA level between 20-30 ppm, I chlorinate using a metering pump, but given it injects a metered amount of chlorine into the water once per minute, it is much like the continuous dosing you get with an SWG

 

[257WbyMag]

Running a higher CYA level with your SWCG typically results in better performance and longer cell life.

 

[duraleigh]

My question is is it necessary to get the CYA level up to 60?

That level is suggested because it is assumed you have an outdoor pool with no cover. Since all your pools have covers, there is no need for the CYA to be that high and where you have them is fine.

 

[crek31]

Just out of curiosity, if a person is going to run an SWG pool with 30 CYA, what are the minimum, target and shock FC values? Or at that CYA does the Non-SWG chart work?

 

[BoDarville]

darbyj62:

Since your chlorine demand seems to be rather stable at your current CYA, then I would hold it at that level at least for now. That said, you will need to continue regular testing to see if the chlorine demand begins to increase as the water warms up. One way to gauge this is to perform periodic OCLT tests. If you pass the OCLT but the rate of FC loss during the day increases, then you may need to add CYA.

 

[JasonLion]

Just out of curiosity, if a person is going to run an SWG pool with 30 CYA, what are the minimum, target and shock FC values? Or at that CYA does the Non-SWG chart work?

I really don't recommend trying that in an outdoor pool. It will only work if you run the SWG continuously any time the sun is up. It will significantly reduce the PH stability and it will dramatically reduce the cell lifetime. If you do go this route, use the non-SWG table.