SLAM almost complete?

[linuxninja00]

Happy 4th of July!

Long time lurker and BBB practice follower here. We just inherited a 30k IG pool with the purchase of our house. Finally got all moved in on 6/30 and was able to remove the cover from the pool. There was some algae on the bottom and sides, but it wasn't a green swamp. From what I can tell, the previous owner didn't know what he was doing. These are my initial results with my trusty TFT100 kit

FC - 0 (expected)
PH - <6.8
TA - 0 (went immediately red, forum says that means my PH was 4.5 or less)
CH - 50
CYA - 100 (sigh, we've got a tablet user here!)

So on 7/1 i loaded the truck up with bleach from Wally World and got my FC levels to 39 as directed my PoolMath. Monitored that and kept it there, while brushing the pool. Also vacuumed some to waste before bleach addition since I figured i could use some water change out due to CYA. I also added some PH up as directed from a post from Chem Geek, to try to raise it from acid bath levels. Yesterday, 7/3, I vacuumed the bottom completely and backwashed the 60sq ft Hayward DE filter. From the morning of 7/3 to morning of 7/4 FC went from 39 to 33, no CC. This morning's test results:

FC - 33
CC - 0
PH - 7.5 (though i don't think that's accurate during SLAM right?)
TA - 110
CH - 50
CYA - 100

Given that my water is crystal clear and no CC, it sounds like I'm in the home stretch of SLAM. Tonight I'll do the OCLT to see if we're good. I just wanted to see if I'm doing everything right here. I've never had a SLAM process go so quickly . Once SLAM is done, I know I probably should work on TA and CYA, though i'm having SWCG installed this week, so I don't need to go too much lower, maybe CYA 80?

Thanks for your time!

 

[Mr Bruce]

Do a dilution test for CYA. Use 50/50 pool water/tap water then add the R-0013 then mix. Then use the tube with the dot in the bottom. Double that number for an approximation of what the actual number is. If it truly is ~100, you are correct, drain 1/5 and 80 will be good for the SWG.

 

[tim5055]

100 is the limit of the CYA test, so you have to do a diluted test. I find this the easiest way to do it. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. The problem is that when doing a diluted test not only do you multiply the rage of the test you multiply the error rate of the test, so results are a ballpark - not an absolute. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.

Pool water......Tap or distilled water.........Multiply result by

....1...................1................................2
....1...................2................................3
....1...................4................................5

 

[linuxninja00]

Do a dilution test for CYA. After you mix the pool water with the R-0013, pour half out and refill with tap water then use the tube with the dot in the bottom. Then double that number for an approximation of what the actual number is. If it truly is ~100, you are correct, drain 1/5 and 80 will be good for the SWG.

Thanks for the dilution test info, that's a new one for me. I do think it's pretty close to 100, I could still see the dot really close to the 100 mark. Obviously the test is a bit subjective, but better safe than sorry. I'll give that a shot too!

- - - Updated - - -

100 is the limit of the CYA test, so you have to do a diluted test. I find this the easiest way to do it. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. The problem is that when doing a diluted test not only do you multiply the rage of the test you multiply the error rate of the test, so results are a ballpark - not an absolute. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.

Pool water......Tap or distilled water.........Multiply result by

....1...................1................................2
....1...................2................................3
....1...................4................................5

If I understand the chart correctly, if I use 1 part pool water and 1 part tap/distilled, i'll multiply my reading my 2? If i have to use 1 part pool and 4 parts tap, i would multiply the result by 5?

 

[tim5055]

If I understand the chart correctly, if I use 1 part pool water and 1 part tap/distilled, i'll multiply my reading my 2? If i have to use 1 part pool and 4 parts tap, i would multiply the result by 5?

Let's hope you don't have to do more than a 1-1, but yes you are correct.

 

[linuxninja00]

Dilution test performed. CYA reading in the tube is just over the 50 mark, so 50-55ish i'd guess. Could err on the high side and call CYA 110.

 

[tim5055]

Dilution test performed. CYA reading in the tube is just over the 50 mark, so 50-55ish i'd guess. Could err on the high side and call CYA 110.

Yes, err on the high side. The big downside to the dilution test is that when you multiply the sample you also multiply the error rate by the same factor.

As the tube makings are not linear what may appear to be 55 could easily be more than that (meaning that half way between 50 - 60 is not 55). I would call it 120.

 

[linuxninja00]

Ok. Should I finish out SLAM first before changing out water or start tackling it now? Looks like rain in the forecast here today, could get some filling help from mother nature

 

[tim5055]

Ok. Should I finish out SLAM first before changing out water or start tackling it now? Looks like rain in the forecast here today, could get some filling help from mother nature

Changing the water = less chlorine needed, I'd vote to change water first & use the free water.

 

[domct203]

Ok. Should I finish out SLAM first before changing out water or start tackling it now? Looks like rain in the forecast here today, could get some filling help from mother nature

I would drain a bit to take advantage of that. No need to stop the SLAM, just adjust FC after filling for your new CYA level

 

[linuxninja00]

Update: 7/5 Morning update

OCLT test held and I lost <0.5 FC. Seems like SLAM has passed! Spent much of the afternoon while grilling, draining the pool and filling. From about 12:30 until 7pm . CYA reads 90 now, better but a little more to go to hit 80 target for SWG. Guess it takes quite a while to make an impact in 30k gal .

Thanks for everyone's help, we're well on our way to swimming!