Run around at pool store

[miker1755]

At some point in the recent past, Pool Doc said to keep my pH at 7.0. Now that my basic problem is maintaining a CL level SEEMS to be under control, should pH stay around 7 or the more normal typically recommended of 7.4 -7.6?

[AnnaK]

Hi Mike,

In post #7 in this thread Ben advised to drop pH to 7 using muriatic acid. His goal, if I understand it correctly, was to avoid further scaling since your calcium hardness was very high.

I just looked at the numbers you posted in your chemical chart. The FC and CC look great! Yes, it makes sense to have CC = 0. That's the entire point of it! Good work. Unfortunately, there were no test results for alk (TA) and CH. Ben was hoping to be able to determine why your CH is so high. Until he can look at this thread again and refresh his memory it would be best to keep the pH low. One of the mods will make sure Ben takes a look at this and advises you further.

[miker1755]

I have reposted additional testing stats as requested to include TA & CH. When testing for CH, titration to change sample from red to blue. Mine is really kind of purple more so than blue, but blue after sitting for a few minutes. Additionally the sample seems to have something that appears to not totally dissolve and I'm wondering of my chemicals are ok or is what I am seeing "normal"

[AnnaK]

Thanks Mike. Chlorine looks good. Ben may have some comments about the TA and CH.

[miker1755]

While waiting for the Pool Doc's comments and recommendations, can someone opine regarding the tradeoff between maintaining a higher FC level due to higher CYA levels and draining and replacing pool water to reduce CYA levels making higher CL levels un-necessary?

[aylad]

I run a high CYA pool on purpose. (80-90 ppm). I lose less chlorine daily, and I can dose every 2-3 days instead of daily.

[miker1755]

Does a high CYA level actually mean you loose less CL daily or is your CL level high enough that even after 2-3 days your CL level doesn't drop to the point where an algae bloom can get started?

[PoolDoc]

Regarding calcium and alkalinity -- did you watch the Taylor interferences videos? How did those results compare to yours?

Regarding high CYA + high chlorine (HiC2) -- we had a pro & con discussion among the moderators and the PF Team members, and the downsides most people were concerned with were

1. The need to use EXTREMELY high chlorine levels to clear mustard or black algae, possibly over 50 ppm. These levels can take a very long time (3+ weeks) to drop.

2. Difficulties with pH testing (see the Taylor pH interferences video -- stickied in the Testing section)

Janet (Aylad) runs a near HiC2 pool (CYA levels almost identical to yours) with few problems, but otherwise, I was the only one completely comfortable with the HiC2 approach. However, since that debate, we've done some testing that suggest the pH test IS accurate with high chlorine levels, IF you read the test within 5 - 10 seconds. If you let it sit, before reading it, you'll get bogus results.

For what it's worth, I've been running a large (200,000 gallon) commercial pool at CYA ~90 and FC ranging from 5 - 25 ppm (typically 12 - 20 ppm) this season, with ZERO complaints. No one has noticed, except the health inspector, who commented that the chlorine was "a little high - 10 ppm" (it was really about 20 ppm that day!). I've repeatedly asked the lifeguards if anyone has the pool being irritating, and none of them have.

This pool has always been extremely prone to mustard algae, possibly because it's right on the Tennessee River, and I've noticed the algae will try to return with levels get below FC=10ppm.

Regarding the algae problem, my preference is to take the chlorine to 30 ppm, and hold it there. If that doesn't solve the problem, the next step is to add small amounts of sodium bromide, creating a small unstabilized bromine residual. Without the presence of DMH (dimethyl hydantoin, used in formulating bromine tabs), bromide is converted to bromate (non-regeneratable) in a matter of days.

So . . . personally, I would NOT recommend trying to lower your CYA level. But, not all my moderators and Support Team members agree. (Yet. )

I did want to ask a question about your bucket test: when you added the soda ash, no clouding occurred? No sediment formed on the bottom? Can you try again, with these guidelines: http://www.poolforum.com/pf2/showthread.php?16992 ?

[miker1755]

Regarding high CYA + high chlorine (HiC2) -- we had a pro & con discussion among the moderators and the PF Team members, and the downsides most people were concerned with were

1. The need to use EXTREMELY high chlorine levels to clear mustard or black algae, possibly over 50 ppm. These levels can take a very long time (3+ weeks) to drop.
My black algae seems to survive no matter what but I haven't trield CL levels that high!

2. Difficulties with pH testing (see the Taylor pH interferences video -- stickied in the Testing section)
Do you recommend I keep my pH around 7.0? My saturation wheel readings indicate that my pool will be better off (I can't remember if it was to be corrosive or otherwise) at 7.4 - 7.6

I saw no cloudiness and assumed the sediment on the bottom was the soda ash (washing soda) so I assumed that was to be expected. I will re-review the thread and re-run this weekend.

After having dumped so much borax into the pool, should I be backwashing my DE filter even though my pressure remains acceptable?
Just FYI, I took back 40# of pucks and 25# of shock to the pool store today so I am pleased with the PF approach. KUDOS TO THE TEAM! ;-)

Currently it seems I have to add 1/2 gal of CL ever 2-3 days but am still trying to fiddle with it to get a better baseline.

Does a high CYA level actually mean you lose less CL daily or is your CL level high enough that even after 2-3 days your CL level doesn't drop to the point where an algae bloom can get started?