De-Lurking After Drain and Refill

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G

gatorgrad

0
Dec 28, 2014
8
Phoenix, AZ
Started lurking 6 months ago after buying a new house; pool looked ok on inspection but water chemistry was terrible (CH over 1100 and CYA at 180) but too late to drain in Phoenix without risking damage to the assumedly original 15+ year old plaster which is already on it's last legs. Bought a TF-100 and struggled through the summer with on and off yellow algae and bits of black algae in the pocked plaster... it was hard to SLAM with the CYA level so not sure I ever did it right. We put in a new variable speed pump but still have the original DE filter (did have it cleaned and they said the membranes were still ok but they wouldn't risk full disassembly)

But finally got around to draining and refilling... so here's to starting from scratch! :p

Current test results

FC - 0
pH - 7.8
TA - 180
CH - 275
CYA - 0

I just added a bag of cal-hypo shock to get FC in the pool.

Next steps look like getting acid, dropping the pH, aerating, and adding solid CYA (I've heard in a sock?).

Thanks for a great forum... trying to get the rest of my 'learning' done before replastering in the next year or two (and probably adding a SWG and new filter too...).
 
Update: Checked FC levels after an hour or so and FC at 11.5; will check again in the morning for OCLT.
On a side note, I should be able to use this info to help refine pool volume, right? Calculating mine now based on how long it took to drain based on the rental pump's rating... so not very sure.
 
Welcome to TFP !
Your doing a great job so far. You've gotten the best test kit and seem to have a good understanding of your water chemistry.
I'd stop with the cal-hypo as your fill water CH may be high. Your in range now for your CH. Use bleach for your FC till you get the SWG if your going that route.
Your correct with putting the CYA in a sock. Throw it in the skimmer basket or hang it in front of a return jet. I'd shoot for a level of 40 for your CYA.
Your TA is high but you seem to understand that also. Your TA will be in a good place when your PH is pretty stable, even if it's out of range on paper. If you get an SWG you want to get it down in the 60-70 range.
Keep us posted on how things are going.
 
Thanks all! Yes, cal hypo was a stopgap for poor planning :(. My first measurement for OCLT came back at 9 against 11.5 but I retested twice and got 11 each time... So maybe not enough coffee?
My pool is pretty irregular so measurements are tough... Will see if I can post a picture later, you all might like to see the pink tile and lion head water feature!
 
Yes, using chlorine or MA to zero in on pool volume are the easiest I believe. Put it what you think you need. Test before and 30 minutes after addition then go to Pool Math and use the bottom "effects of adding chemicals" plugging in the amount and strength of additions, then vary the pool volume at the top until it tells you the change that equals what actually happened. If you do this for both FC and pH you should be able to prove your answer. Then just pick the 1000 gallon number closest to it and that's your number. No need to be more exact than that. And of course you can do this a few times to eliminate any testing inconsistencies.
 
Ah thanks! Using Pool Math for adding 1 lb of 65% cal hypo to cause a +11 FC I get a 7k gal pool. Will keep trying to dial it in... I'll use that as a more conservative volume for now; I assume underestimating volume is safer (won't have chemical overshoot)...?
 
Ok, came home tonight and tested again. Everything same but FC went to 0 (wow! Thanks AZ sunshine...)

FC 0
pH 7.8
CH 250
TA 180
CYA 0

Added 19 oz dry CYA in a sock in the skimmer, 64 oz 14.5% acid, and 121 oz of 8.5% bleach and started the water fan/aerator thing. Will check again before bed to see how that dialed in (I did pool math with 7k pool size)
 
Don't bother testing the CYA for a while. It can take up to a week to fully register on a test. Just assume the CYA level you aimed for is there and adjust your FC target for it. What CYA level did you aim for ?
 
I aimed for CYA of 20 to start assuming I am right about volume. I checked FC just now and it was only 5.5 with 0 CC so not sure if the chemicals are still mixing in (pH maybe went down 0.2). These are about half what I was targeting from Pool Math (FC 11 pH 7.2) Which implies volume is 14k... But I don't think the volume is that far off, will check again in the morning...
 

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If it's been 30 min's or so things are mixed good. As long as your pump was running the whole time. Always have your pump run at least 30-40 min before taking any tests.
Your FC is good now for your CYA level. 5 would be a good target for the CYA level of 20. The min is 2.
 
Ok - so a few days in and have been monitoring closely. Yesterday kept FC in the pool all day (5.5 in am 2.5 in pm) so I think CYA levels are coming up (still significant amount of dry CYA volume in the sock though). I added another 121 oz of 8.5% bleach and this time it increased FC from 2.5 to 15.
Looking at the previous bleach bottle to this (which raised from 0 to 5.5) I don't actually see a chemical content on the bottle... So maybe that first bottle was not 8.5%? The labels are marginally different but were all intermingled at wallyworld... Very odd. This one suggest volume closer to 7k again.
MA additions so far have not been modulating pH as much as the calculator suggests, not sure if it's pool volume estimate related, or if other factors are in play... 2 quarts are lowering pH maybe 0.2 or so. Am having trouble with being confident on levels with the k1000 test in the TH100. Did see the very start of TA lowering but can tell it is going to be slow.

Before adding last night:
pH 7.5 (ish)
FC 2.5
TA 180.. But almost 170

Added 121 oz 8.5% bleach and 64 oz 14.5% MA
30 min later

PH 7.3 (ish)
FC 15
 
You can help the CYA dissolve faster if you give it a good squeeze once in a while to help it along.
In the future don't buy any bleach that doesn't give the percentage labeled. Most bleach is 8.25%
Let that FC of 15 drift down.
 
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