Newbie getting ready for 16-18 day vacation

[Micwtx]

Trying to plan for our 16-18 day vacation. Have a family member willing to come by and add chlorine but want to make things as simple as possible for her. Have a plaster pool (maybe little plaster left), 25k gals. Had algae start after not adding chlorine in 4 days due to family surgery, so did SLAM for 4 days Have been running pump 24 hours for slam but normally 12 hours daily (have timer). Everything LOOKS great so let the chlorine drift down, chlorine did drop 4 points in 24 hours but temps were 93-95.
Last testing done with t-100 kit:
FC8, PH7.4, TA140, CYA60(kind wonder if not closer to 50 as I can still see grey dot in bottom of tube at 60).
Am doing oclt tonight to see if finished slam process. Have used cal-hype 73% for slam and have slowly convinced hubby to let me try 10% liquid chlorine for normal use instead of cal-hypo. Have also been using trichlor pucks in floaters to try and keep chlorine levels up.
Wondering if I can put our solar cover on (it looks like large sheet of blue bubble wrap to me), maybe run pump for 8 hours and have family member add premeasured liquid chlorine daily lifting a corner of the cover and pouring in.

Question:
Can I run the pump with the cover on?
Can I add chlorine with the cover on?
How do I calculate how much chlorine to use if using a solar cover?
Does it matter if the chlorine level get progressively higher while I am gone?
Do I need to get the other chemical levels down before starting all of this?( CYA, PH TA etc)

I would appreciate any suggestions. I am hoping not to come back to too much of a problem as hubby is already muttering about filling in the pool or selling the house. It took me several days of research and discussion to convince him to try following the TFP method of pool care. Don't want to screw things up! LOL!
Thanks in advance

 

[lightmaster]

When you list your test result, list them like this so we can read and understand them easily:
FC: 8
CC: ??
pH: 7.4
TA: 140
CH: ??
CYA: 60


Don't know much about using a cover as I don't use one, but I know you want to stay away from cal-hypo and trichlor. You don't list a CH test result, and if your using cal-hypo, I suspect this might be high which can cause scaling on your plaster. More importantly, using trichlor as your primary chlorination will drastically raise your CYA and make normal daily chlorinating difficult to maintain, and slamming all but impossible as it continues to climb. Take a look at the Chlorine/CYA chart in Pool School (linked in my signature) to see how quickly the daily target and shock target climb. Yours isn't too bad, but anymore trichlor and you'll likely push it into the "not recommended" range. Also, always round your CYA up, so if the dot disappears at a glance between 60 and 50, call it 60. Has to be at a glance though, if you stare at it, you'll still see it.

Over such a long time 2-3 weeks, its probably impossible to say how much chlorine to add to maintain your daily target. Rain, temperature, sunny vs cloudy, high UV days vs low UV days.... basically just the weather in general plays a huge role in how quickly the chlorine is burned off in your pool. I don't know how much of an effect a cover will have on all that, but I've heard you still need to remove the cover so the pool can outgas and burn off any CCs. It would be better to see if your neighbor or whoever can test for FC and you just have a chart printed off like this:

FC level	Amount to add
4	50 oz
5	40 oz
6	30 oz
7	20 oz

Those are just random amounts in that chart, so please don't actually print that off and go by it.

Your neighbor could just test the FC, pour in the amount on the chart, and then call it a day. Also, perhaps every 3 or 4 days, they remove the cover and then replace it the next day to let the pool breathe.


As for other levels, your pH will naturally rise over time, so I'd lower that down to 7.2 a day or 2 before you leave. Your TA is a little high, but will come down as you add muriatic acid to lower your pH over time.

As for chlorine building up, if you keep adding a set amount of chlorine that is more than the amount that is burned off, it might build up over time, especially under a cover. As long as its under your CYA's shock level, it shouldn't hurt anything. But, if you have them test FC each time and add what's needed to raise back up to the target level, then you wouldn't have to worry about that anyway, they'd just be replacing the chlorine that has been lost.

 

[FattyLumpkin]

I run my pump with the cover on all the time. So, yes, it's fine. I also have added chlorine with the cover on many times, and with no ill effect. As light notes, it's almost impossible to predict your daily FC usage. Assuming your SLAM is complete, I would suggest following the rule of thumb of 2-4 ppm FC loss per day, and just add enough 10% or 8.25% chlorine to offset that loss + a small buffer, and call it a day. Even if it's over-dosed on bleach, you have room to allow your FC to raise well above target before you reach shock level at your CYA, at which point you'd might not consider swimming in it. However, you're not around, and it's 2-2.5 weeks we're talking about, so I'd personally err on the anti-algae risk side and add *more* as opposed to *less*. Also agree with pulling the cover off once a week or so to "breathe" -- my CC builds up if I don't uncover the pool and allow the UV at it.

I think your other levels are fine presently, despite a relatively high TA of 140. If you were leaving for months and your pool was saltwater or had some other pH-raising effects, you might want to lower your pH and TA, but I think you're fine at 7.4 pH at that TA for 2 weeks. Again, if it were longer, the higher TA could lead to a spike in pH that you'd want to try to address the TA before your extended time away.

 

[Micwtx]

Thanks Lightmaster and FattyLumpkin for your replies. I thought of using the cover to help minimize the leaves etc from getting in while we are gone. There is a neighbors pecan tree hanging partly over the pool. Removing the cover to vent has would not be possible as it is huge and takes two people to move and install or remove. Plus the family member who will check pool has just had cataract surgery so can't do lifting like that. She might be able to do a chlorine test using the quickie test (the one using 5 drops and checking yellow color on chart), but not sure about having her do more than that. We do have test strips that might be simpler for her but not too accurate. Would adding borax help? If we do a partial drain to lower cya how much would we have to drain? Can we use a cya lowering chemical to do it? Hubby having second eye surgery today so will be near pool store and can get chemical.

 

[mknauss]

Can we use a cya lowering chemical to do it?

There is no chemical that reliably lowers CYA. Only one is fresh water. Do not fall for the pool store hype that they have something that works.

Why do you need to add borax? It will raise your pH. No need for that as the pH will naturally rise over time with a higher TA.

The color test block for FC will be fine, just make sure your helper keeps it dark yellow to orange. If the pool is covered it will not take much chlorine daily to achieve that.

Take care.

 

[Micwtx]

Mknauss, I asked about borax as there was thread discussion on here about using mule team borax in pool as a type of algaecide. It also helps reduce chlorine loss and once in pool it is like cya it does not burn off so not constantly having to add more.