Newbie with yellow/black mold, stratospheric CYA.

[red-beard]

Maybe this is worth another thread in a different section, but I measured 6GPM with the recommended Superior Pump 91330 1/3 HP through a 5/8" x 50' garden hose.

That's some 38hrs for a 80% water exchange... is there something obvious I'm missing that is bottlenecking the pump more than would be normal? Is it perhaps worth grabbing a couple of the 25ft 1-1/2" hoses? (I need a 35ft run) .

Yes, the garden hose is your limiting factor. I bought an adapter so I can use the 1.5 inch pool vacuum hose. You remove the 3/4" hose adapter from the submersible pump. My pool is 25,000 Gallons and with 1/3 hp and a 1/6 hp pumps running I can drain my pool in about 12 hours.

Some places make a flat hose, like a fire hose, that can do the same thing. Sometimes called a backwash hose. You may need hose clamps and adapters to make it work.

My Setup with the pool vacuum hose.


My two pump setup. The 1/6 hp pump has the 3/4 inch garden hose.

 

[AtlasAirborne]

Yes, the garden hose is your limiting factor. I bought an adapter so I can use the 1.5 inch pool vacuum hose. You remove the 3/4" hose adapter from the submersible pump. My pool is 25,000 Gallons and with 1/3 hp and a 1/6 hp pumps running I can drain my pool in about 12 hours.

Some places make a flat hose, like a fire hose, that can do the same thing. Sometimes called a backwash hose. You may need hose clamps and adapters to make it work.

Whoa, you weren't kidding... with a 50ft, 1.5" backwash hose ($25) and careful avoidance of kinks it's pushing about 44GPM, so a bonus... 630%? Crazy difference - thanks for the suggestion!

Tomorrow's test battery will tell whether I did a good job or not.

As an aside, just to make sure I'm reading the CYA test properly, should I be filling until

- The black dot first disappears momentarily when a drop of treated sample is added to the tube

- The black dot remains obscured after resting for ~5sec after more sample is added

These points are often very different, and I've read mixed suggestions on which is correct.

 

[Newdude]

These points are often very different, and I've read mixed suggestions on which is correct

I’d like an answer here as well. My sample always settled after a bit and became clearer. I’ve been told by others that theirs stays milky forever. Is there 2 sources of R0013 that behave differently? Maybe salt/LC behaves differently? I dunno.

either way, I’d instant glance and call it. Even if the solution stayed the same, your brain plays tricks on you and sees/doesn’t see what’s there. It’s how you do/don’t see your nose at any moment. It’s there, believe me it’s there. But it’s not. You know ?

*apologies again for making TFPers cross eyed this morning again with this analogy.

 

[red-beard]

The best way to run the test.

In full sunlight, fill the sample tube to a mark, say 80 ppm. Hold the sample tube at waist level and do a quick glance. If you see the dot, fill to 70. Repeat until you cannot see it. You do not have to use more chemicals to re-read the test. Just pour the liquid back into the dripper bottle. Make sure you shake the dripper bottle all the time. At TFP, it is recommended to just test to 10 ppm increments.

 

[AtlasAirborne]

Thanks - sounds like max turbidity is the goal, then (in which case my CYA may be even higher than I thought

 

[red-beard]

Better to err high than low.

 

[AtlasAirborne]

Well I couldn't have hoped for a better result - after the dilution:

FC: 1ppm
CC: 0ppm
CYA: 48ppm

After addition of chlorine (went a little high, but that's okay):

FC: 9ppm
pH: 7.7
TA: 170ppm
CH: 250ppm

Given that the TA is high, I added muriatic acid to drop the pH to 7.0 (and have since aerated it back to 7.3), but the TA remains constant at ~170ppm. Is this normal? Is it even a problem I need to solve?

For the CH, I'm assuming I can just use some unstabilised cal-hypo for my chlorine until it's back up around 350ppm and then switch back to liquid chlorine?

 

[red-beard]

That is a great use for Cal-hypo.