About to Slam, What is the source of high numbers?

jayinc11

Active member
Mar 21, 2016
27
texas
I am preparing to SLAM, pool has not been running aok and most times in fact not at all. Had been reduced to just throwing chlorine granules for the better part of summer or lock down period by a care taker...achoo achoo! Equipment is fixed up, vacuumed bottom while set to waste and added tap water about twice, brushed, etc. Baseline was 0.5 both TC & FC. PH 7.4, TA 40, T.Hardness 650, CYA 0. Then I dropped 4 tablets, 18 jugs of 5% chlorine and 12lbs arm & hammer baking soda, pump was on 24hours.

Today numbers are both TC & FC 3, PH 8, TA 120, T.Hardness 775, CYA 30.

What is the source of high Total Hardness and so far did I over do something, seeing PH went from 7.4 to 8? Based on these should I continue to add more LC or what should I do next?
 
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HermanTX

Gold Supporter
May 20, 2020
774
Katy TX
Are you doing your own testing or is this Pool Store results? Is your pool green or unclear, do you see algae? Just trying to understand why you want to SLAM. For a CYA of 30 your FC should be 4-6ppm. Is a jug equal to a gallon? So you could add more LC. Now before you SLAM (if you really need to) you should lower your pH to 7.2 per the guidelines SLAM Process
Have you tested your fill water? Could that be a source of calcium? Mine has high TA but low on calcium.
 
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jayinc11

Active member
Mar 21, 2016
27
texas
Yes I had algae all types green, mustard and I believe black (this is still there, will post a pic) since the pool really wasn't running. From last and this week it's gone after vacuuming and brushing. Own results so I thought the next step was to slam, no? A jug's a gallon of LC with 5% sod. hypochlorite. The water has improved so significantly and quite clear other than last few debris pieces and another vacuum run to get out some minimal dust.

If my numbers get to target I guess I can hold off slamming and see how well they hold?

Haven't tested fill water. It's N. Dallas...N. Texas, could be the source.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,728
Prosper, TX (DFW)
If you have algae you should SLAM. In DFW we have tons of options for liquid chlorine (Walmart, Lowes, Home Depot, etc.) that are in the neighborhood of 10-12%. I would look at those, particularly walmart's Pool Essentials, rather than the 5% you are using.

Do you have the proper test kit for the SLAM?

Also make sure you use muratic acid to drop your pH to 7.2 before you SLAM. Hopefully you can be done with the SLAM in a week or so.
 

jayinc11

Active member
Mar 21, 2016
27
texas
Pool is algae free as of last Friday, all cleared now. Water clarity is spot on but when I brush I stir mhhh... dead broken pieces of leaves I would say nothing another vacuum run won't clear. Does that mean I don't need to slam and should just work the numbers into target range and that's all?
Yes I have the kit. Also added 24oz of MA this evening to lower PH per slam guide.
As for the chlorine jugs my reasoning was I get 15% CL from 3 jugs @ 1 buck each vs 7.5% CL @6.48 a jug from wally. So I had picked these up in bulk and have quite a few left to run through, not to mention almost 80lb of granular chlorine which I now feel so averse to dumping in the pool. HD, Lowes 10-12% sounds good enough to me.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,728
Prosper, TX (DFW)
If you are unsure if you have algae, I would recommend you doing a Overnight Chlorine Loss Test (OCLT). Basically you test your FC after sundown, and then again before sunrise. If you have lost < 1 FC, then your chlorine is not battling any algae. If you lost more than that, you have algae somewhere.

My gut feeling is that you still likely have algae somewhere, and a SLAM would be beneficial. Note that since you have already lowered your pH and bought the chlorine, I would recommend bringing it up to SLAM levels and then doing the OCLT tonight to see if you need to continue the SLAM.

 
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jayinc11

Active member
Mar 21, 2016
27
texas
OK. Reading around I came across the concept of aerating water-one method is turning return jets to face upward or another is installing a venturi in those return jets. Is this something good for a pool all the time or only when it's needed?
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,728
Prosper, TX (DFW)
Aeration raises pH. Typically not something you would want to do around here since your pH will naturally rise. For example, if you just lowered your pH to 7.2, I bet it naturally is mid to upper 7's by the weekend. I've found that mine likes to be 7.8-8 and will remain there for a while, so I let it stay there before I knock the pH back down.
 

jayinc11

Active member
Mar 21, 2016
27
texas
Some general questions...

Typically is 25 lb of dry stabilizer way more than most people usually need say in a year, with a well maintained pool that you may slam once a year, at most if at all? And what is the shelf life? If location matters, it's hot hot N. Texas.

How do you bring down slam level CYA it was say 60 or 70 and the goal is 40? Is it by some draining some water or exposure to sunlight takes care of that?

Haven't quite understood what is the source of high calcium in pools? Mine's down to 575 from about 8-900 from 4 weeks ago-ish.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,321
Laughlin, NV
Once you have your CYA at your desired level in late spring you will lose about 3-5 ppm per month, in addition to any lost due to overflow from rain. 25 lb of stabilizer could last several years, and as long as kept dry, will be fine to use.

To lower your CYA quickly you must remove the water from the pool with the CYA and add fill water that does not have CYA.

The source of calcium in pools is from fill water added due to evaporation unless one is using calcium hypochlorite to chlorinate with. If your CH has dropped as you say, you have replaced 30-40% or so of your pool water with fresh water over that time, or your test data is not accurate.
 

jayinc11

Active member
Mar 21, 2016
27
texas
I brush daily and have vacuumed the heck out of this erstwhile pit. I knew in the process I will be replacing lotsa water; and two days ago I drained/filled a little over a foot. So those percentages make sense. Fill tap water CA is 100. From having read recommended levels my CA target is 400-plaster pool, though I have seen maxes of 225 to 400 elsewhere. Not sure what to make of those.

And what are sources of high TDS? My TDS meter says 975, and wifey was told 2600 from pool store. This was before the 1 foot drain & fill.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,728
Prosper, TX (DFW)
I brush daily and have vacuumed the heck out of this erstwhile pit. I knew in the process I will be replacing lotsa water; and two days ago I drained/filled a little over a foot.
I may have missed it, but why are you draining? Typically that is only done for high CYA or Calcium. In a quick scan of your thread I saw calcium of 400 and CYA of 60, neither of which are too alarming.
 

jayinc11

Active member
Mar 21, 2016
27
texas
I may have missed it, but why are you draining? Typically that is only done for high CYA or Calcium. In a quick scan of your thread I saw calcium of 400 and CYA of 60, neither of which are too alarming.
400 is target, my numbers have been above 750+ since I started keeping track of everything about a couple of weeks back. In addition is high TDS 2600, whose source I have no clue of,...???

BTW instructions to add dry pool stabilizer says to very slowly pour into a skimmer. Should the pool be running on filter or recirculation?
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,728
Prosper, TX (DFW)
Ignore TDS, this is a pool store thing.

What is your CYA right now after draining? If you were at 60 and drained a foot, I'm not sure you would need to add stabilizer. If you do need to add, the recommendation is to put it in a sock that is dangling in front of a return (seems odd, but the concept is for it to dissolve in your pool but not be touching any of the plaster).
 

jayinc11

Active member
Mar 21, 2016
27
texas
Will ignore tds and thanx for sock idea, it's brilliant!
CYA is 25, was 35 a day prior b4 draining.

Post drain/ fill up
CYA 25
FC&TC 3.5
TA 75
PH 7.2
CH 575
CSI -0.11

Pre-drain / [target]
CYA 35 [40]
FC&TC 4 [7]
TA 110 [70]
PH 7.6 [7.7]
CH 825 [400]
CSI 0.55 [-0.3-0.3]

My day to day CYA target is 40 and FC is 7, based on recommended levels page. App says to add 1.8lbs dry stabilizer, and 131oz of LC.

I drained because I am getting concerned with continued hardness levels. I have 2 pitted holes on the first step and I can see a blister. Granted the holes have been there for at least 4 years. Now to fix these holes they have to be exposed correct?
 
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jayinc11

Active member
Mar 21, 2016
27
texas
Pool has developed stains over the years. They are on some of the sides and in patches on the floor here and there. Granted, these started cropping up from 5-6 years ago but I think they have increased during from summer when the pool wasn't operating. I have been brushing everyday for the last 3 weeks, my guns put Rambo's to shame-says wifey, not sure she's just hyping me up to keep working on the pool and I haven't noticed ... noticeable increase in desserts serving, IDK. Anywho, are the stains black algae or what are they if not that.
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