New Pool Owner, Total Drain and Fresh Water Fill

[rdr1719]

Hi there! Sorry in advance for the long post.

I've been deep in Pool School for a couple of weeks and am finally starting the balancing process today. We recently purchased a home with a salt water pool; the previous owner walked us through his care routine when we got the keys in Feb. He told us he took water to the pool store a *couple of times a year* and threw salt in whenever he felt like the chlorine was low (!!!!!) until he could smell it again. Knowing nothing about pools at the time, we thought "great, a low-maintenance system!" Fast-forward to now, warming up so we are starting to use the pool. We noticed the water just didn't seem right, so I started googling and found TFP. Ordered the Taylor K-2006-C and K-1766 and started testing. The chemistry was WAY off. I'll spare you the horror of the numbers. I shudder for the previous owner now that I know that whenever you smell chlorine it is CC and means there is something growing.

Salt, CYA, and TA were all high. CH was reading >1000 (I realize now I had a fading endpoint issue). Took a sample to Leslie's just to get a ballpark that we didn't somehow get a dud test kit, their numbers actually weren't too terribly far off of ours (other than CH 593). Because the calcium in our tap water is high at baseline, and the previous owners obviously didn't do any proper chemistry care, we decided to do a complete drain and fill. (I contacted multiple companies about an RO treatment and all said our TDS were too high and would ruin their membranes.) This may not have been 100% necessary but we thought it would be better to start fresh.

SO! We have brand new water. SWG has been powered off since we drained. Luckily it is very clear, we do have some scaling on the waterline tile that we will be tackling at a later time but nothing on the plaster that we can tell. After the drain I noticed one specific area of the pool smelled like a gross pond and noted that there was some yellow on the wall (not visible when pool is full). I am 80% sure after reading that it's mustard algae. It is on the wall that gets the most shade and there is none on the floor of the pool; I scrubbed it with the brush and hose water when the pool was empty and it got slightly lighter but definitely didn't come off.

Current Test Results:
FC 0
CC 0
pH ~8.1 est (acid demand 3 drops to 7.4, 5 drops to 7.2, 7 drops to 7.0)
TA 160
CH 140
CYA <30 (suspect 0, solution was completely clear and obvs new water)
Salt 600ppm
Water Temp 73F

The Plan:
Add 51oz 20 baume muriatic acid to pH 7.2: Transchem Muriatic Acid 1 gal Liquid - Ace Hardware
Add 62oz dry stabilizer to CYA 40 (will likely add less and test so I don't overshoot): Robot or human? (I know not to use Clorox pool salt but is their stabilizer ok?)
Add 1.9 gallons 10% Chlorine to 16 (I know I can use bleach but this seems like a decent price at $6.99/gallon for 10%?): HTH Liquid Chlorinating Chemicals 1 gal - Ace Hardware
Add 23lbs calcium chloride to CH 350 (this seems like a lot?): O-ACE-sis Granule Calcium Hardness Increaser 25 lb - Ace Hardware
SLAM with CYA of 40 (I could aim for CYA 30 but with the sun in PHX I think the extra buffer will help)
OCLT when SLAM seems complete (CC<0.5)
FC to Mustard Algae Level for 24 hours after SLAM complete, thoroughly brush pool

Add CYA to SWG ideal of 70
Add salt to ideal ~4200-4500 (will get non-clorox non-pool pure salt)
Adjust pH and CH as indicated
Start SWG as FC levels are coming down from SLAM, adjust run time and % as indicated to goal FC 5

Lower pH and aerate to bring TA down (I suspect our pH will drift up, and I want to keep CSI down to reduce scale)
Maybe add borates to further buffer
MAINTAIN our beautifully balanced TFP water =)

Am I overlooking anything? Does anything I listed need to be completed in a different order? Are any of the chemical supplies I linked terrible? Pool School was a lot of information, so typing all of this out was helpful and your feedback is appreciated!

 

[MITBeta]

Looks like a good plan. Is your fill water softened? If not, you may only want to go to 250 on the CH. Were you able to get a good volume measurement while filling? If not, take the opportunity while sneaking up on your targets to dial in your gestimate.

 

[MITBeta]

Looks like you should be able to get liquid chlorine at Home Depot in Phoenix for $5/gal.

 

[Rancho Cost-a-Lotta]

If not, you may only want to go to 250 on the CH.

This is a good plan. The lower CH will help offset the higher TA.

 

[rdr1719]

Looks like a good plan. Is your fill water softened? If not, you may only want to go to 250 on the CH. Were you able to get a good volume measurement while filling? If not, take the opportunity while sneaking up on your targets to dial in your gestimate.

As far as we can tell, the fill water (and our hose water) is not on our softener system. We unfortunately didn't keep good track of the actual filling time, so will definitely hone in on our actual gallons as we add chemicals. We do have the builder blueprints, which is where we got the 11,640K from.

Do you suggest the 250 target because we will only see increases due to evap? I just tested the hose water and it is about CH 150. Just want to make sure we don't damage the plaster or cause corrosion with the 250, but I would love that because apparently calcium chloride is expensive.

 

[rdr1719]

This is a good plan. The lower CH will help offset the higher TA.

Once we get to the lowering TA part of the plan, would you suggest bringing CH up to ~350 or will 250 be sufficient?

 

[rdr1719]

Looks like you should be able to get liquid chlorine at Home Depot in Phoenix for $5/gal.

After continuing my online shopping Walmart has it for $4.63!

 

[mknauss]

I would be hesitant to add any calcium. Better to maintain an elevated TA and pH to keep CSI under control. The CH will nearly double by the end of the summer.

 

[rdr1719]

I would be hesitant to add any calcium. Better to maintain an elevated TA and pH to keep CSI under control. The CH will nearly double by the end of the summer.

So you would suggest leaving CH ~140 and leaving TA alone for now? I would think I could then monitor the CH rise throughout the summer and aerate as needed to lower TA and keep CSI in check? Just concerned about corrosion and plaster damage with low CH, but I'm new to this!

 

[mknauss]

I am just hesitant for you to add calcium. You must get a mix of Colorado River and Salt River water in your area. I suspect your CH from the tap will increase as you get into summer.

You will have to diligently monitor pH (keeping it between 7.6 and 8) to make this work for the new few months.

Just my thought -- lets see if others are more concerned about the CH level.

Also check that salt level. Seems rather high but I do not have experience with that SWCG. The salt ppm also effects CSI.

 

[rdr1719]

I am just hesitant for you to add calcium. You must get a mix of Colorado River and Salt River water in your area. I suspect your CH from the tap will increase as you get into summer.

You will have to diligently monitor pH (keeping it between 7.6 and 8) to make this work for the new few months.

Just my thought -- lets see if others are more concerned about the CH level.

Also check that salt level. Seems rather high but I do not have experience with that SWCG. The salt ppm also effects CSI.

I was surprised by the salt level as well as most that I have have seen here on TFP are 3000-3500, but I found the manual for our system online and confirmed it says 4000-4500ppm is the ideal level for it. "The Powerclean Salt Ultra operates best with a salt range of 4,000 - 4,500 ppm. The cell will continue to operate with a minimum of 3,000 PPM and up to 35,000 PPM without any adverse effects to the unit."

I didn't consider that we might see changes in the CH of our tap water based on the time of year! That is a very good point. I think I will raise to 250 to ease my mind about corrosion and monitor closely this year.

 

[mknauss]

As the SWCG will operate at 3000 ppm, I would target your salinity at 3200 ppm or so. It will rise with time (fill water, muriatic acid, sweat, all add salt).

Your call on the CH. Do investigate ways to use soft water for make up water in the near future. Really makes a difference in pool water chemistry maintenance.

 

[Rancho Cost-a-Lotta]

Do you suggest the 250 target because we will only see increases due to evap? I just tested the hose water and it is about CH 150. Just want to make sure we don't damage the plaster or cause corrosion with the 250, but I would love that because apparently calcium chloride is expensive.

Here's my take. CSI is more important than any one factor that makes up CSI. My fill water CH is 125 and had to drain down the pool annually to keep it in range before adding a softener to my fill line. CH will be the only reason you'll need to drain/refill in the future. I would be very hesitant to add CH and have the utmost trust in @mknauss.

I would take a close look at Pool Math and develop a plan to control CSI without the adding calcium chloride. I ran your numbers with a TA of 120, pH of 7.8, and salt at 4250 at 84 degrees and came up with a CSI of -0.15. You can expect your CH to rise 150 ppm+ by the end of the season.

I didn't see if you posted the TA of your fill water, but it's likely high based on the current number. There's no pressing reason to fight that number down at this time.

Just my 2 cents.

 

[rdr1719]

Update! You all convinced me not to add calcium, so we skipped that and will monitor throughout the summer. Started the SLAM Friday afternoon, Sat morning FC had dropped very slightly so we did one more day. Sun morning FC did not drop overnight, water was still clear, and CC was <0.5 (we never saw CC over 0.5). We also thoroughly brushed the pool twice a day during the process, the suspected mustard area more. Sun morning raised FC to mustard level, the sun made it a challenge to maintain but we managed. The pool is looking really good!

From the chemical additions we now suspect our pool is closer to 9000-9500 gallons. Hopefully we can confirm/narrow that range with the salt addition. I do have a couple more questions:

-Can I start adding salt before FC drops below 10? I know some of the tests (esp pH) are unreliable with a FC over 10.

-Same question for CYA. Can I add to achieve ideal SWG levels before the FC falls too much? I don't want to raise it too soon because I do need FC to come down from SLAM levels.

-Any tips for the CYA test? I feel like it is so subjective. I have read here on TFP to do it with your back to a bright sun and the container at waist level. Is it done when the black dot is completely not visible? There is definitely a point where I feel like I see it very faintly but if it was just a glance I might not see it, or maybe I can "see" it just because I know it's there?

Next steps:
Add CYA to SWG ideal of ~70
Add salt to ideal ~3200-3400
Adjust pH and CH as indicated
Start SWG as FC levels are coming down from SLAM, adjust run time and % as indicated to goal FC 5
Monitor CSI and ideally adjust with pH/TA. With a lower CH I will be keeping pH and TA higher. As CH (and water temp) starts to rise throughout the summer I can lower pH/TA to maintain a good CSI. (Does that sound right?)

Thank you for sharing your expertise with me!

 

[mknauss]

-Can I start adding salt before FC drops below 10?

Yes.

Can I add to achieve ideal SWG levels before the FC falls too much?

yes - as long as you are assured the SLAM process is complete.

-Any tips for the CYA test?

Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is in logarithmic scale. So it is not viable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

(Does that sound right?)

yes

 

[Rancho Cost-a-Lotta]

Does that sound right?

It sounds like you studied up and have a good understanding of what you need to do short-term and long-term. Great job!

 

[Rancho Cost-a-Lotta]

Just a couple tips.

Add CYA and salt in stages and sneak up your target. You don't want to overshoot as the only way to remove is through water exchange.

For both, wait 24 hours before final testing. Don't start the SWG until the salt is well mixed.