First test results, what to do with TA/CYA/CH pre-SLAM?

[hilaryjoyce]

Hi all!

We finally got our kit in the mail and I sat down and measured the dirty details for our 9500 gallon above-ground pool, which are:

FC = 0 (unsurprisingly, we've been just periodically adding some packets the previous owners left to keep it from being green)
pH = 7.2
TA = 50
CH = test turned purple even with the pre-adding 0012 trick. Should I dilute with tap water and try it again? Or is "red/pink" more purple than I'm anticipating and I should persist and add more reagent? I didn't want to waste it so I quit fairly quickly.
CYA = 0 (sample was clear as glass alas)

We were hoping to do the whole SLAM thing this weekend, but I'm not sure which other things need to be fixed first. Bringing the CYA up will mean we lose less chlorine, so I'm guessing we should do that first? Do we need to do it a full day before, or is a couple hours fine?

The TA is a bit low, but should I adjust that after? I'm really not sure what to do about the CH at all--with a vinyl above-ground pool this seems less of an urgent issue, or am I misunderstanding?

The pool is very very cloudy but not terribly dirty looking, though the bottom could be covered in algae for all we can see it right now. It was open and only partly drained all winter, and the previous owners used those pucks for chlorine, so I'm a bit surprised CYA is so low! It got "tested" by my MIL's dog last weekend, and as far as I know she's still alive, so it's not the swamp it once was.

Thanks for any help you can provide!

 

[pooldv]

All that is required to start a SLAM is PH, CYA and FC. Details here, SLAM Process

 

[hilaryjoyce]

Thanks! I wasn't quite sure if I could SLAM at 0 CYA, but some googling of the forum suggested it's possible, just will result in more FC loss to sunlight. After starting the SLAM at 10 ppm midday today and seeing it drop only to 7.5 ppm after two hours despite mid-afternoon (Canadian, though, haha) sun, it feels manageable!

Is that a reasonable drop? The pool is blue but VERY cloudy--can hardly see a foot down. We vacuumed up a huge patch of green goop in the bottom yesterday and did some more vacuuming & cleaning of the filters, so the worst of the visible organics are on their way out.

CC was at 1.5 ppm after half an hour of the initial 10 ppm add, fwiw, so I'm hopeful about it not taking too long to get <0.5 CC and <0.5 drop, but the cloudiness feels more challenging. If we get the first two goals of a SLAM but have made no progress in water clarity, what do we do? The filter's been running for weeks now, and we've been backwashing frequently if not obsessively often. How does SLAMing affect cloudiness? That part hasn't been clear to me in the guides.

 

[pooldv]

We do not recommend SLAMing without CYA. Or operating a pool at all without CYA for that matter. Not even in sunny Canada! Here is the process for a SLAM, it includes adding 30 ppm of CYA. SLAM Process

 

[hilaryjoyce]

Got it! Bought some stabilizer on the way home from work and added enough to hit 20 ppm (being cautious in case it wasn't actually 0, I'll test once the sock is empty and re-evaluate). Of course, now there's a thunderstorm so I don't know if this is going to be the most effective OCLT, but we're early yet so it's no big deal.

My husband was home today so he was able to add bleach every couple of hours to keep it from crashing. We lost 4.5 ppm overnight last night, and then dropped 2.5, 5.5 (midday!), 3.5, 4, 3.5, and 1.5 ppm in between adds today (aiming to maintain at 10 until the CYA goes up, right?). Good thing he was home or it would have been a hot, chlorine free pool for most of the day! I definitely see how the CYA is going to make this easier.

I also picked up a replacement pressure gauge, and I'm looking forward to actually knowing how backed up the filter is instead of just guessing arbitrarily!

- - - Updated - - -

Ps. here was our starting point, since I love seeing other people's "progress pics" and hopefully will eventually have the same thing. I'd take a current picture but it's a dark and stormy night, so I'll have to do that tomorrow. It's much improved in colour already!

View attachment 50563

PPS. I'm loving this forum, reading it top to bottom, right down to studying chem_geek's graphs.