Newbie SLAM Question

[pvnefl]

Hi all. I'm coming in as a victim of my own ignorance, so here goes.

I have a 2800 gal above ground vinyl Bestway pool (per signature) that I've sustained on Clorox tablets and shock. Things were great for a couple of years, but last year I had algae issues and this year, opening the pool, tests are off the chart. Like so many others, the CYA built-up out of control. So I drained as much as I could and refilled, ordered the intex SWG, took the tablets out, and am going to SLAM. However, I'm waiting on my TF-100 test kit.

In the meantime, I brushed the pool, have been running the filter 24/7, and corrected PH (roughly) using a PH meter since my FC is way beyond the ability of my test strips to quantify.

My question now is, while I wait on the test kit, what FC should I try to target? I've been diluting samples at a 3:1 pure to pool water ratio and can get consistent test strip results, but the ranges are of course broad. My CYA is between 60 and 120. I've brought FC up to about 24..just looking for advice on how high I can bring FC safely until I'm able to get reliable test results from the TF-100 to precisely calibrate. I want to do what I can to inhibit this algae until I can perform a proper SLAM based on tests.

Thanks already for the info I've gleaned from this site, and appreciate any advice for this interim situation of the next few days.

Edit: The SWG is not yet connected. Chlorine additions as of yesterday have been and will be 10% liquid chlorine throughout the SLAM.

 

[wireform]

Hi and welcome
To answer your last question first, by adding 5ppm daily till the kit arrives @2800 gallons =18 ounces 10%.
The problem is more where your CYA is at now and you can only find out when your kit arrives. Don't do anything or add anything till you run the full test line up and post them back here for further comment. If your CYA is still in SWCG territory it my make sense to slam as is since your pool is small and achieving slam may be doable .

 

[pvnefl]

Thanks for the advice! The test kit showed up and I've spent the last day trying to get the hang of testing (eg, when the evening FC was higher than morning without having added any chlorine, I figured some operator error was probably involved).

I got three consistent readings, so I think these results are pretty accurate:

FC: 42.5 (not really sure how it got this high. Must have been off the charts from the beginning due to the tablets I was using and/or the opening granular shock I applied)
OCLT: 1
CC: 1
TA: 220
pH: 7.7 (read via pH meter, since FC is too high for drop test)
CYA: 80 (+/- the novice test reader adjustment)
CH: 175
Temp: 74F
Salinity: Not tested, SWG is off

pH has been drifting upward, so I sealed off the aerator valve on the return to limit bounce-back. TA is actually down from 240, because I have added pH down daily when I get readings over 8.0. Should I pick up some MA instead and ditch the pH down?

I also have not added chlorine, since I'm well above SLAM FC levels unless my CYA is actually 110. Water is clear, still vacuuming up/brushing dead algae from the bottom. We really struggle to keep organics out of the pool due to trees nearby. I've been cleaning a ton of algae out of the cartridge filter daily, but this morning the cartridge was much less green than in prior days, so things appear to be improving.

Am I on the right track to continue nudging pH down to slowly lower the TA? As far as the SLAM process, do I leave well enough alone until FC drifts back down to the recommended 31?

 

[pvnefl]

FC is down to 32.5. Bright sunny day certainly seems to have helped, but wow! CC is 1 at most.

 

[pvnefl]

Well, I think I flubbed last night's test reading because FC tested at 39 multiple times this morning, which shouldn't be possible since no chlorine was added. I think it's a much more reasonable 1-day drop considering the water is very clear. I am still getting the hang of catching the transition from "very faint pink" to "completely clear" on the FC test, and morning sunlight is far easier to see in than indoor testing after dark. At around 70-72 drops, I get a quick transition from dark pink to faint pink, but then it doesn't seem to change at all for 6-7 additional drops before an almost imperceptible shift to clear.

CC was 3 ish (again, tricky to my eyes since I'm looking for the transition back to faint pink?) so we're still SLAMing. But I've still not had to add any chlorine for a few days since I started so high.

 

[duraleigh]

I am still getting the hang of catching the transition from "very faint pink" to "completely clear" on the FC test,

The end point of all these tests work the same and it is VERY important to do them correctly.

You add drops slowly as you get close. Then, very slowly continue to add one drop at a time until the LAST drop you just added makes NO FURTHER color change. Then subtract that last drop from your total and the test is complete.

 

[pvnefl]

I am continuing on with the SLAM, but am running into some interesting fluctuations and am wondering if they are normal.

FC finally dropped down to SLAM level of 31 and the past few days have required small 8 oz LC additions to maintain. I've passed a couple of OCLTs, but now last night I lost 2ppm, so that fails. The biggest indicator my work is not done is I am still brushing clouds of brownish stuff off the bottom of the pool. I'm not 100% if it's pollen or algae, but am assuming algae for now since I started with an algae problem.

However, my CC is 0 and has been for days. I observe no perceptible shift from clear when adding the 5 drops of reagent. Would it not be expected to have some readable CC if I'm failing an OCLT and brushing algae off of the floor? Or is this just indicative that the FC is doing its job? Based on this thread (Visible algae, but with CC of 0 ~~ I'm confused), I'm inclined to think it's the latter.

I have a week before we go on vacation and hope I can complete the SLAM by then to let the SWG maintain while we are gone. I plan on raising the FC to SLAM levels before we leave as a protective buffer anyway, but if I am still vacuuming visible algae at that point, is the best option to raise the FC to Mustard Algae FC, cover with a solar cover and let the filter and SWG operate while we are gone?