Pretty good water chemistry

[djbilo]

After my total water replacement I have continued to adjust the water chemistry.

Right now my concern is a fairly sudden onset of reduced water clarity compared to when the water was new a few weeks ago. Have kept the FC at 3 or better.

OCLT is .5 ppm and will check tonight again. Cartridge filter exhaustively cleaned yesterday with an 8 hour pump run...2 four hour runs 12 hours apart.

Today, 3 pm central numbers:

FC 7.5
CC 0
TC 7.5
TA 60
CH 140
CYA 40
pH 7.2

Suggestions? More circulation time? Still do have a leak but seems isolated to suction retun and when the vacuum hose adapter is installed the leak is greatly reduced....so can leave it installed to help that situation...

 

[Smykowski]

I would bump the run time by a couple hours and keep the FC a little higher (10ish?) for a few days. See if that clears it up.

 

[zea3]

Your CH needs to come up to at least 250 ppm for a plaster pool. 3 is the bottom of your recommended FC range, if it could have dropped below that for a day or two you may be on the edge of an algae bloom. Try bringing the pool to shock level for 24 hours and run the OCLT again.

 

[djbilo]

Your CH needs to come up to at least 250 ppm for a plaster pool. 3 is the bottom of your recommended FC range, if it could have dropped below that for a day or two you may be on the edge of an algae bloom. Try bringing the pool to shock level for 24 hours and run the OCLT again.

Checking all these numbers....this shows my min/max/shock level for 40 CYA:

CYA (Stabilizer):40 Minimum FC:3 Target FC:5 Shock FC:16

Pool Calculator shows this for current #s and conditions, to raise CH (sanity check):
CH current 140
Goal: 250

Add 265 oz by weight or 212 oz by volume of calcium chloride
or add 352 oz by weight or 404 oz by volume of calcium chloride dihydrate.

Pool Calc shows -.78 and if I reach these numbers it calculates to -.32 (in the acceptable range if I'm reading this right, as compared to -.78 which is beyond the -.6 acceptable for plaster pools).

RIGHT? - that sure seems like a lot of calcium chloride!

TA of 60, raise to 100 (?) by adding 153 oz by weight or 122 oz by volume of baking soda

 

[y_not]

I'd leave the TA alone, assuming your pH is stable. If not, at most, start with 70ppm TA and see where that puts your pH long term.
It's so easy to raise, but a lot of work and time to lower. So go easy on it.

Did you measure your CH /w a speed stir?
Definitely do an OCLT at full shock levels, too little CL to play with otherwise.

 

[jblizzle]

Play with the pH in the calculator. If you raised that a bit, that will have a pretty substantial impact on the CSI.

I left my CH low after a refill and kept the pH a little higher to compensate ... knowing that in AZ, the CH will rise due to evaporation so I did not want to intentionally add CH.

Edit: although if you need to SLAM, don't raise the pH first. And I too would not raise the TA much of at all.

 

[djbilo]

Did you measure your CH /w a speed stir?

I don't yet have a speed stir but I have repeated the test a few times close together so I have good confidence with the #s and my swirl method is pretty much like it was in chem lab by hand, back in the day.

I'm in the SLAM mode and will do the OCLT overnight, after a long pump run until the wee hours, and see how it shakes.

 

[y_not]

Just to clarify, when you do an OCLT, leave the pump running between the 2 tests, after dark and before dawn.
In order to get an accurate indication of consumption by any organics that may be present in the water, continuous circulation is critical.

 

[djbilo]

FC last night was 15 ppm; CC .5 ppm, TC 15.5.

This morning, FC was 14 ppm; CC was 0, and TC was therefore 14 ppm.

The water looks somewhat better. Pump ran all night.

I am going to re-test tonight as well.

 

[y_not]

It sounds like you're riiiight on the edge, something was beginning to grow in the water.
As technically you passed the OCLT, but if the water clarity improved, you're surely killing off the beginnings of a minor algae bloom. That point where the water still looks more or less OK, but it's beginning to "dull" a little.

Keep SLAMing it, keep FC up by staying on top of those CL additions. It's OK to add a little more than an FC of 16ppm to compensate for UV loss, outgassing and consumption by organics present in the water. But more, is not better, as you'll lose it waaayyyy too fast if you go too much above FC 16.

Also, keep in mind that you will lose more CL during the day due to UV exposure, as it burns off the CL some, even with the CYA in there, which only slows the process, it doesn't stop it.
Keep on it in the daytime, so you don't dip below an FC of 16, as much as possible. Then plan your attack time for evening, when the sun goes down, as without the UV present, the CL has more of a chance to work and be more effective, since it stays longer and has more "killing power" if you will.
Not that CL can't kill algae during the daytime, it's just that as the CL is busy killing "oxidizing" algae and other organics, it's also being broken down by the sun's UV rays. See? Yeah... CRAZY!!

When you do an OCLT, you want your FC @ 16, not 15ppm. But it's still a good indicator that you need to keep SLAMing that puppy!!!
SLAM it until it sparkles, sparkles as much, or more than tap water.