Starting off right - New inground

[JCarsten]

I've been lurking in the just getting started section for a few days. I am (hopefully) a few days away from filling my new in-ground pool. Construction is chugging along. The remaining big items are concrete decking, the liner, hooking up the equipment and filling.

Particulars on my new system:
12,500 gallons
in-ground vinyl liner
SWG and a sand filter
Received the TF-100 kit yesterday

We'll be filling from an irrigation well we have on our property. So I know that I'll be starting with 0 chlorine and 0 CYA. The water in our area is hard. However, I don't have a reliable way to draw water from the well until our contractor puts a faucet on it (later this week or early next).

Assuming I'll be starting with absolute base groundwater, I am trying to formulate my plan of attack to get the chemistry right as quickly as possible once I fill. That being said, I have a few questions:

1. I assume I'll want to use bleach to set the chlorine level on day 1 and not count on the SWG to build it up slowly over time. That sounds to me like a recipe for giving algae a foothold. If I do this, should I hit it with any bleach while I am filling? Or should I wait until it's filled, then dose based on the pool volume and targeted FC level?

1a. With 0 CYA, and assuming I would want to do my initial chlorination with bleach, what FC level should I target with my first bleach treatment?

1b. For my initial FC level with bleach, should I target FC level based on the CYA I have at the time of fill (none) or should I based my initial FC level on the CYA level I am trying to get to eventually (in a few days to a week)

2. Should I also add CYA (sock in skimmer) as I am filling? Or immediately after it's filled?

3. Should I start running the SWG right away, even after the bleach treatment? If so, what's a good recommendation for starting run time and SWG operating %?

4. What about other tests (TA; pH; CH; etc.)? Should I run those as soon as I get the pool filled? Or should I just assume that I have 0 chlorine and 0 CYA, and do my initial treatment based on that. Then run the full battery of tests a few days later once I get the chlorine and CYA up to level?

5. Does it do me any good to test while I am filling the pool, just to get an idea of the baseline water? Once the faucet is attached to our well, it should be easy to get a sample from the faucet and know the readings from the water going into the pool. Does that buy me anything?

Thanks in advance for the huge amount of information I am about to start requesting.

 

[jblizzle]

1. Yes adding bleach is a good idea, although no huge hurry. When it is full and the pump is running, add 2ppm of FC and maintain it between 1-2ppm until you add the CYA. Once the CYA is dissolving, then use that to determine your minimum FC level. I would start with about 50ppm of CYA, measure in a week and then raise to the SWG recommended level.

2. You could tie the sock on a noodle while the pool is filling if you want, or put it in front of the return jet or in the skimmer.

3. You should not start the SWG until at least 24 hours after adding the salt (which you could put in while filling). A lot of FC will be lost until the CYA is in the water and as the CYA builds up, the output is going to have to be changed ... trial and error here.

4. Fill the pool, circulate for 30 minutes, then test everything (except CYA) to see what needs to be adjusted.

5. That will give you the CH and TA level and a rough idea of the pH. Does not really buy you much.

 

[JCarsten]

Thanks Jason. So on #1, I am OK to get it full and then just maintain 2 ppm of FC while getting the CYA dissolved and the salt in the water? I was concerned that if I didn't hit it immediately with bleach I was at risk of an algae outbreak.

<edited because I can't spell worth a darn>

 

[jblizzle]

Add 2ppm after you get the pump on and try to maintain that ... as the CYA dissolves, raise the FC as needed according to the FC/CYA Chart. Just assume the CYA level is at your target and test after a week.

 

[JCarsten]

Add 2ppm after you get the pump on and try to maintain that ... as the CYA dissolves, raise the FC as needed according to the FC/CYA Chart. Just assume the CYA level is at your target and test after a week.

That's the part that has confused me as I read the various posts and pool school. So day 1 I add 2 ppm of FC and the CYA. From what I have read, the CYA can take several days to dissolve. So let's say day 1 I put in 2 ppm of FC and enough CYA in a sock to target a CYA of 70. For a SWG, the chart says a CYA of 70 should have a FC target of 5. If I put the CYA in on day 1, and don't test CYA for a week, at what point do I try to bump the FC to 5?

Another question just occurred to me. Sorry for being all over the map. But I've never maintained a pool before. And with this project still in construction, so much of this is still conceptual for me. But if I have the SWG running after I get the salt dissolved and the liquid chlorine at 2ppm, how hard is it to inadvertently overshoot 5 ppm with my SWG?

 

[jblizzle]

When the CYA is dissolved from the sock assume it is all active. I would also suggest not adding all 70ppm in one step.

Not a big deal if the FC gets a little high, just turn the SWG output down.

 

[JCarsten]

Cool. One other thing. Why did you recommend 2 ppm of chlorine as a starting point with no CYA. Wouldn't I need to go higher since there is no CYA to protect the chlorine? Or were you saying, add 2 ppm, then kick on the SWG and let it make up for the rest?

 

[jblizzle]

I am saying you need to maintain the FC between 1-2ppm and yes it will be lost to the sun quickly, so you will have to test and add more.

With no CYA in the water, having a higher FC level is very harsh and could damage the liner if you raise it too high for too long.