Variable Speed pump and Balancing the Chemicals

[scott.lopez]

To start off with, thanks very much for the guidance that has been provided on this web forum. I've learned a lot that has helped me to better understand how to manage a swimming pool.

I'd appreciate help in understanding the following:

I am having difficulty maintaining the pH, our pool was plastered about a week ago with Pebble Sheen and it seem the Ph constantly wants to go to 7.8 or higher.

I have been adding acid on a daily basis to try to bring this value down. I've had some success but it seems like a constant process.

We have a variable speed pump that I'm am running around the clock at 1730 RPM (47 gallons per minute) that turns the water over roughly three times a day (as advised by the government), I don't mind running the pump around the clock, I think it costs us $16 per month (using 247 watts). I run the pumps at 2750 in the evenings to push anything on the surface to the skimmers.

One thing that running the pumps constantly does do is to push a little bit of water over the spill in the spa to the main pool, it's really just a trickle given that there are 6 returns, and two skimmers that have venturi systems in them. Would this be causing the pH to rise like it is? Should I reduce the pump run times?

The chlorine level also seems to be dropping, I had it at 1.5 this morning and this afternoon it dropped to 0.25. It was a sunny day in Dallas with a high of around 77.

With a CYA of 42 and the max limit recommendation of 50, I have been adding bleach to the pool to compensate for the loss of Chlorine. Using the pool math calculator on this site, I've been following the advice.

Pebble tech tells me to use the npconline.com numbers to determine proper pool chemistry. According to their site the FC should be between 1 and 3.

To combat this loss, I have the chlorinator (Jandy Fusion 2) with 3" trichlor tabs set to 2, I upped it to 3 this afternoon in an attempt to get more chlorine in the pool. Leslie's told me that the value on the chlorine generator should be set to 1. My concern about increasing the chlorine output is the increase in the CYA, I really don't want to have to drain the pool.

I've included the PDF from the WaterLink software. I've found that the pH is about 0.2 less on the Taylor test kit than on the WaterLink DataMate software. I adjust the chemicals accordingly. All other chemicals seem to accurately match between the Taylor test kit and the WaterLink.



# measurements:

pH: 7.8
FC: 0.25
TC: 0.46
Combined Chlorine: 0.21
Hardness: 199
Alkalinity: 84
CYA: 42
Copper: 0
Iron: 0


Thanks

 

[pooldv]

It is expected that new plaster will cause PH rise. Does the Nature 2 also have a "mineral" cartridge? That will add copper to your pool eventually leading to staining, green hair, lime green water, etc. Lots of folks here are spending a lot of time and money trying to remove copper from their pool. I highly recommend not adding copper to your pool intentionally. Good job keeping an eye on your CYA and keeping it below 50. Keep adding acid to lower your PH and keep it at 7.8 or less. Adding the acid will lower your TA. Letting your TA drop as low as 60 will help reduce PH rise. But, it can take up to a year for your plaster to fully cure and your PH to stop rising.

Your chlorine level should be higher. Chlorine should be set based on CYA and the Chlorine CYA Chart. Always keep it at target and never let it drop below minimum.

Start here, Pool School - ABCs of Pool Water Chemistry

No need for 3 turn overs or any other number. That really does not apply to residential pools. I run my pump at 1100 rpm to skim and make chlorine with my SWG? 3-4 hours in the am and 3-4 hours in the PM shojld be more than enough.

 

[scott.lopez]

Thanks for the reply. The Nature 2 does have a mineral cartridge, I don't think the pool people have installed it yet. I don't think it's necessary given what I've read and don't plan to use it.

I'll keep adding acid and bleach in the evening. Also, if the CYA is less than 50 tomorrow I will look into raising the TriChlor level again. Will not apply the mineral cartridge.