Complete drain chemistry setup questions gunite pool

Poolnewb22

New member
Apr 28, 2022
2
Mid-Atlantic
Hello! I have been a reader for the last year learning a ton here, and managed to get through my first season as a pool owner with clear water. So thank you all.

We had our pool renovated last spring and then converted to salt mid-summer, the renovation company handled the chemicals for the first month and I don't know what they put in, but I think a lot of unnecessary chemicals, jacks magic, algicide, and trichlor tablets. It is a kidney shaped pool in the mid-Atlantic region so doesn't have a cover unfortunately. We had a few dead mice, a dead bat, a dead red-spotted newt (apparently skin is toxic) and our CYA and Calcium levels were starting to get high near the end of the season. After each of the animal instances I shocked the pool with 10% bleach to high levels (25ppm) due to high CYA (pushing 70-80ppm). We also have a baby who will be able to use the pool this summer. When the pool company closed the pool they drained 1/3 of the water, I am also on Well water, so need a truck to fill. Due to all of the above and needing to get 1-2 trucks to top off the water, I made the decision to just do a full drain and re-fill and figure it is a good time to get the chemicals right from the start. They are coming next week on Monday to Drain, Tuesday to fill, and Wednesday to open the pool.

I just wanted to make sure I had my chemical plan on track, I read a few posts about vinyl pools but nothing about a full drain on a gunite pool.

My plan is as follows:
1) Pool company will add salt upon opening. (but no other chemicals I think?) Last year they added Jacks Magic Magenta to the pool along with an algicide upon opening.
2) Add liquid chlorine until chlorine level is 3-4ppm, not worried about overshooting this initially. Will check 2x a day initially to make sure level is maintained until CYA and SWG are in balance.
3) Add granular CYA in sock to get to 30ppm (I want to be careful to not get the CYA too high again as shocking the pool becomes quite challenging). I am in the mid-Atlantic so the sun may not be as bad as the south, and will gradually increase CYA until I can maintain a good chlorine level with my salt cell. I know the guidance is 60ppm plus, but want to test to come up with the correct number for my pool. I really want to keep this as low as possible and am willing to replace my salt cell more frequently, so am targeting 30ppm-50ppm to make shocking the pool easier and more effective.
4) Get PH in line 7.4-8.0. Last year due to the plaster and SWG the levels would rise and I would need to add muriatic acid 2x a week.
5) Get Total alkalinity in range, 50-90ppm, last year with the acid additions and small water feature this number was hard to keep much higher than 50ppm.
6) Increase Calcium, the pool company told me the water trucks are around 70ppm calcium, I will add enough to get to 300ppm initially. I was reading on the Orenda website that higher calcium can actually be OK to maintain LSI. I don't want to go crazy, but will try to get this around 300ppm.

My main questions are
-do I need any Jack's magic or other product? Do I need an algicide (I don't think so as long as i maintain enough free chlorine)?
-looking for advice on a SWG with a slightly lower than 60ppm CYA level to make it easier to shock. Again - in mid-Atlantic, and will go through daily testing to ensure adequate chlorine from SWG.
-what would a good first shot target be for calcium, is 300 too high to start with?
-making sure i'm not missing anything with the opening plan


Thank you!
 
do I need any Jack's magic or other product
Likely not with trucked in municipal water.
Do I need an algicide
Nope. While algecide can be a pre-treaent fot algae, it also wastes your FC that don't allow algae in the first place. So it's kinda counter productive if you lose your FC and then need the algecide with no FC. 🤦‍♂️

looking for advice on a SWG with a slightly lower than 60ppm CYA level to make it easier to shock
Keep tabs on the FC production as you promise to. Follow the FC/CYA Levels religiously. Minimum is not an OK level. It is the outskirts of Swampville. Stay clear of Swampville, happily ignorant 20 miles away in TargetRangeVille. It's BEAUTIFUL in TargetRangeVille. I never dipped below target range and never needed to shock in 8+ years with my old pool. The one time I lost my FC over the winter..... boom. Swamp. When my cell reached end of life and I had zero clue how to dose liquid chlorine because the SWG always kept me at or above target range.....boom. Swamp. Moral of the story : stay in or slightly above target range and you will never need to care about the shock/SLAM level based upon your 70 or 80 CYA.
what would a good first shot target be for calcium, is 300 too high to start with
That's probably a good target. All fill water adds more calcium so you want a little wiggle room for the inevitable rise. For us on the east coast our fill water is relatively low calcium, but there is still some in there.
making sure i'm not missing anything with the opening plan
The plan is great. Did I stress the importance of target range ? It's the most important part. If you are there at all times, we have plenty of time to tinker and figure anything else out, like the Ph or CH levels. They will never give you a swamp.

Edit : to drain fully you need to confirm either a hydrostatic valve in the pool shell, or low enough ground water, or the empty pool becomes a boat and will float
 
Edit : to drain fully you need to confirm either a hydrostatic valve in the pool shell, or low enough ground water, or the empty pool becomes a boat and will float
Thank you. Great point, I was under the impression if I drained it the day prior and then filled the following day this wouldn't be an issue? I believe less than 24 hours for a once in a few year drain is ok?

never needed to shock in 8+ years with my old pool.

Understood, my combined chlorine got a bit high 1-2 times last year so I did shock due to that, but otherwise mainly the shocking was due to dead animal, bat, etc incidents. If my FC stays high and is checked frequently, I guess I am willing to risk a lower CYA to allow for easier shocking... as I am anticipating more animal issues this year.

Thank you for the guidance.
 
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I was under the impression if I drained it the day prior and then filled the following day this wouldn't be an issue? I believe less than 24 hours for a once in a few year drain is ok?
If the ground water is high when you drain, the pool is a boat and floats immediately like a boat would.

The only way time is on your side is that if you drain without harm, you'll likely have it filled before the next big storm or groundwater rise. (y)

Keep us posted.
 
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