I've inherited a mosquito-breeding pool, and need to close it.

[PoolDoc]

The goal with the floater is NOT to "do a lot of good" but to "dispose of the tabs safely"! Fill the floater up!

OK. Your pH is high enough to be of some concern. Go to Lowes, and buy a gallon of muriatic acid (saw it for $6.50 today). Find a CLEAN 5 gallon plastic bucket with a handle. Fill it with 2 gallons of WARM water. Add 1/8 - 1/4 gallon of acid. Do this OUTSIDE, with sun or safety glasses AND glove on, AND near a gently running water hose at hand. Watch out for fumes. Once you've added the acid, use the water hose to mix the warm water and acid together, by adding some water directionally, to create a current in the bucket.

Leave the hose running, so if you need to rinse off a spill (on you, or on anything else) you can do so quickly.

Carry the bucket to the pool, and add 1/2 gallon of mix to multiple locations. Wait 2 days. Retest pH; if above 7.8, dose with acid again. Repeat til the pH is below 7.8 OR you are out of acid. Make sure you wait 2 days between doses; without circulation it may take that long to distribute.

Using warm water and highly diluted acid should keep the acid mix from hitting the pool bottom where it could be a problem.

Otherwise, my original list still applies.

[DewiMorgan]

Thanks once again, and apologies for my denseness.

I will add more tabs when I get in tomorrow, then, and get the muriatic acid and cheap algicide at the next paycheck. I'm surprised it's so strongly alkaline - I thought oak leaves were acidic. Shows how little I know.

Lessee, how far am I on that To-Do list you gave me?

+ [...] add ALL the chlorine chemicals to the pool [in a floater]. The primary reason for adding this stuff is to dispose of it.
- In progress.

+ Post a list of all chemicals you have INCLUDING CHEMICAL NAMES (not brand or product names!) here.
- Done.

+ Get a cheap ~$10 OTO/phenol red test kit, and post pH test results here.
- Done.

+ Buy a quart of cheap 50% algicide at Walmart (~$15) and dump it in. It won't kill the algae, but the lowered surface tension will probably kill the larvae, without causing future pool problems. If you had more than 10# of chems, add the chlorine first, wait 2 days, and then add the algicide.
- Still to do. Waiting on paycheck. This one's actually to kill the larvae?

+ Get muriatic acid, mix and add per your directions.
- Still to do. Waiting on paycheck. This one's to prevent the acid etching the walls?

+ Go ahead and cover the pool.
- Still to do. Cover has gone missing. Likely in the garage somewhere, which will be an adventure in itself.

+ Post your location and we'll look up winter weather norms, before telling you how to winterize.
- Done.

+ Forget about cleaning up the water: with your budget, it's not an option, even if you use plain bleach.
- Done. *sigh* The hardest one you've given me, but I agree it needed doing


Questions:

1) What does a $15 plastic floater do more than, say, a loose-woven cloth baggie tied around a tab and a brick of wood? Assuming the brick's large enough to prevent the tab touching the sides of the pool, that is?

2) I won't add the other stuff until the chlorine's used up, unless you recommend otherwise: but is it OK to put the muriatic acid and the cheapo algicide in on the same day?

[BigDave]

You don't have to wait for your next paycheck to lower the pH, You have Muriatic Acid and Dry Acid (sodium bisulfate) in your chemical inventory.

Another thought: Can you organize your colleagues to pitch in and try to get the pool back? If 10 more people can put up $15/mo like you are, you may be able to clean it up in the spring.

[PoolDoc]

apologies for my denseness.

No need for apologies; no denseness is involved.

I thought oak leaves were acidic.

Tannic acid -- in oak leaves -- is acidic. But oak leaves are more than tannic acid, & have no idea what their overall effect is. Dunno why your pool is basic; only that it is.

+ Buy a quart of cheap 50% algicide at Walmart (~$15) and dump it in. It won't kill the algae, but the lowered surface tension will probably kill the larvae, without causing future pool problems. If you had more than 10# of chems, add the chlorine first, wait 2 days, and then add the algicide.
- Still to do. Waiting on paycheck. This one's actually to kill the larvae?

Yes

+ Get muriatic acid, mix and add per your directions.
- Still to do. Waiting on paycheck. This one's to prevent the acid etching the walls?

To prevent high pH from causing problems, of various types. But acidity causes etching, not basicity (high pH). Sorry about not checking your inventory list.

You should absolutely do as Big Dave suggested, and use up all acid sources BEFORE you buy more. BTW, trichlor tabs are also acid.

Regardless, follow earlier instructions about adding acid in highly diluted form with warm water, to prevent damage that could occur in an uncirculated pool otherwise.

Questions:

1) What does a $15 plastic floater do more than, say, a loose-woven cloth baggie tied around a tab and a brick of wood? Assuming the brick's large enough to prevent the tab touching the sides of the pool, that is?

Trichlor will destroy most forms of cloth, and some forms of plastic.

2) I won't add the other stuff until the chlorine's used up, unless you recommend otherwise: but is it OK to put the muriatic acid and the cheapo algicide in on the same day?

Yes, just not in the same spot.

[DewiMorgan]

From above list of chems in the shed:
"- TransChem "Muriatic Acid" 20deg Baume Hydrochloric Acid 31.45% - 2 x 1 gal" - unless you reckon it'll be horribly degraded by now, I'll try using those instead?

[PoolDoc]

Muriatic acid doesn't degrade with time . . . but bottles do. Be careful to set things up, so that if the bottle shatters, you are protected (glasses, gloves, running hose!)

If it's still in a box, move the box OUTSIDE before opening it. If you have a large enough plastic bucket, put one gallon in the bucket -- gently! -- and then poke it with a not-sharp stick, to see if the bottle is brittle. If the bottle is OK, proceed.

Be SURE to store the bottles so sunlight does NOT reach them.