Thanks Mike. Chlorine looks good. Ben may have some comments about the TA and CH.
Printable View
Thanks Mike. Chlorine looks good. Ben may have some comments about the TA and CH.
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?
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.
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?
I lose less chlorine. For example. When my CYA is 40-50, I lose 4-6 ppm per day. At CYA of 90, I lose 2-3 ppm per day. My baseline Cl levels have to be higher, but my chlorine loss to the sun is half by running the higher CYA.
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 ?
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.Quote:
Originally Posted by PoolDoc
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?
We don't have good data on chlorine loss, if you follow the Best Guess chart, at different CYA levels. What seems to be true is, the chlorine loss is similar, regardless of CYA levels. However, at HiC2 levels, you have a much, much larger reservoir of chlorine present, so there's a larger safety factor, if you miss a day or have a pool party. And, at levels around CYA=150 ppm, you can usually dose with chlorine just 1x per week.
No wonder that I am confused...
On 6-16-12 @ 10:04 am, regarding a bucket test I was told....
3. Bucket test for lime softening:
fill the bucket w/ ~4 gallons of pool water.
add 1 tablespoon of bleach & mix.
add 1 tablespoon of either pH UP (sodium carbonate) OR Arm & Hammer Washing Soda
cover and wait 24 hours
inspect; note results; recover & wait 24 hours
inspect again; report results
In the forum stickys reagarding Alkalinity & Calcium problems it says:
To perform a lime softening test, you'll need the following:
A white 5 gallon bucket.
A 1 gallon or 1/2 gallon clean milk jug or orange juice container (to measure with).
A Taylor K-2006 test kit -- you will need most of the tests in that kit. (Test kit info page)
A jug of plain 6% household bleach.
A box of Arm & Hammer Washing Soda (from Walmart)
Lids or towels you can cover to cover the buckets.
A plastic or stainless steel tablespoon measure
A clean household long-handled stainless or plastic cooking spoon
The capability to vacuum to waste. <= This is CRITICAL!
To carry out the test:
Use the gallon or half gallon measure to collect pool water.
Fill the first white bucket with 4 gallons of POOL water.
(Measure by adding 4 measured gallons OR by adding 33 lbs of water to the buckets).
Add 1 tablespoon of bleach, and mix.
Test your POOL water's hardness; round result up to nearest 100 ppm
Add 1 tablespoon of soda ash to bucket for each 100 ppm of hardness, plus one more tablespoon.
Mix thoroughly, and cover.
(The water should turn very cloudy, after you add the soda ash. If it does not, ask us what's going on!)
Inspect after 24 hours, and again after 48 hours for settling.
If mixture does settle, test clear liquid from top for calcium hardness.
10. Verify that sediment is a thin layer that can be vacuumed up.
I am re-conducting a bucket test and am using 5 TBS of A&H Washing Soda but my original test only had 1 TBS....which is correct?
(My CH is at 400, which according to the abbreviations listing is "in range" although clearly at the high end.
Also, is soda ash and sodium carbonate the same? My bucket water is cloudy, that's for sure!
Yeah.
For better, and for worse, PoolForum content is 'in motion'.
I can pretty much guarantee you that those bucket tests will be at least slightly different next year than they are now. You got one of the early, "Hey, we can probably solve problems this way!", before I realized, "Hey, we can solve a BUNCH of problems this way, and I need to write a more careful sticky!"