Newbie ??? - Pool looks great but low FC and CYA; High PH

[utell]

I have new pool. Opened mid March this year.

My FC readings have always been low - around .5 to 1.0. Also, my CYA is low or almost non existent. PH is usually high - around 8.2

The water looks and feels great. I have SWG and Delta UV filter as well. I am wondering if the UV filter is doing its job - allowing me to keep the FC low.

I have not back washed the filter yet. Pressure is near start-up pressure.

Any advice would be appreciated.

 

[RobbieH]

Re: Newbie ??? - Pool looks great but low FC and CYA; High P

OK here we go!

First, get that pH in check. That is easy.

It's a good thing your CYA is low, because your FC is low! I'll let the SWG experts jump in, but from what I have read you'll use your cell really quickly trying to keep up your FC level without CYA. That said, is your pool shaded most the time?

 

[Richard320]

Re: Newbie ??? - Pool looks great but low FC and CYA; High P

Robbie is correct.

High pH can cause all kinds of problems, and it is so easy to fix. A couple of cups of acid and it's done.

Have you tested CC? Maybe your SWG is putting out enough, but something's munching on it?

 

[fuzzy_dba]

Re: Newbie ??? - Pool looks great but low FC and CYA; High P

I have new pool. Opened mid March this year.
My FC readings have always been low - around .5 to 1.0. Also, my CYA is low or almost non existent. PH is usually high - around 8.2
The water looks and feels great. I have SWG and Delta UV filter as well. I am wondering if the UV filter is doing its job - allowing me to keep the FC low.
I have not back washed the filter yet. Pressure is near start-up pressure.

First, my pressure doesn't rise that much either but that doesn't mean that i don't backwash; I just don't do it as much or for as long. Your pH needs to come down to 7.5! It'll rise back up, but a little muratic will keep it in check. SWG's have a tendency to cause pH creep anyway. Test yours weekly and keep it in the 7.5-7.8 range, never higher.
Read Pool Schools articles on SWG's.
http://www.troublefreepool.com/pool-school/water_balance_saltwater_generator

To summarize:
FC 3-5 ppm
PH 7.5-7.8
TA 60-80
CH
50-300 for vinyl
220-320 for fiberglass
250-350 for plaster
CYA 70-80
Salt 200-400 ppm ABOVE recommended optimum level

You have got to get CYA in the water to allow the SWG to function correctly. The UV generator may be helping, but was your system designed to have the SWG and UV work together?

 

[JasonLion]

Re: Newbie ??? - Pool looks great but low FC and CYA; High P

UV does very little to improve things in an outdoor residential pool. UV does save dramatic amounts of chlorine in a public pool, because the UV system can break down CC, saving the chlorine that would be required to do that. But in an outdoor residential pool there is hardly any CC to begin with, so nothing much for the UV system to do (unless you are having a pool party). UV will allow you to run at a lower FC level in a public pool, or other high bather load pool, but it does not allow lower FC levels in a residential pool.

 

[utell]

Re: Newbie ??? - Pool looks great but low FC and CYA; High P

Thanks for the replies. To answer:

Pool is shaded in the afternoon. Yes, pool was designed for both SWG and UV. I had my PB do a lot of research on it after I did. I also discussed with people that have them. All loved them. My PB actually put one in his pool that he just built for himself after learning about teh benefits of them. Some say they are overkill for a resi pool; however, my water could not be clearer.

I did a SWG boost for 24 hours. Tested again this evening. FC is 1.0 and CC is .5. PH is 8.0

I have been adding about a quart of acid every other day. Does not seem to bring PH down much.

Should I backwash prior to adding CYA?

Thanks